Down syndrome
Overview
Down syndrome, or Down's syndrome, trisomy 21, is a chromosomal condition caused by the presence of all or part of an extra 21st chromosome
Chromosome 21 (human)
Chromosome 21 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. The trisomy of the 21st chromosome causes Down Syndrome...

. It is named after John Langdon Down
John Langdon Down
John Langdon Haydon Down was a British doctor best known for his description of a relatively common genetic disorder that is now called Down syndrome.-Education:...

, the British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 physician
Physician
A physician is a health care provider who practices the profession of medicine, which is concerned with promoting, maintaining or restoring human health through the study, diagnosis, and treatment of disease, injury and other physical and mental impairments...

 who described the syndrome
Syndrome
In medicine and psychology, a syndrome is the association of several clinically recognizable features, signs , symptoms , phenomena or characteristics that often occur together, so that the presence of one or more features alerts the physician to the possible presence of the others...

 in 1866. The condition was clinically described earlier in the 19th century by Jean Etienne Dominique Esquirol in 1838 and Edouard Seguin
Edouard Seguin
Édouard Séguin was a physician and educationist who was born in Clamecy, Nièvre. He is remembered for his work with children having cognitive impairments in France and the United States....

 in 1844. Down syndrome was identified as a chromosome 21 trisomy
Trisomy
A trisomy is a type of polysomy in which there are three copies, instead of the normal two, of a particular chromosome. A trisomy is a type of aneuploidy .-Description and causes:...

 by Dr.
Encyclopedia
Down syndrome, or Down's syndrome, trisomy 21, is a chromosomal condition caused by the presence of all or part of an extra 21st chromosome
Chromosome 21 (human)
Chromosome 21 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. The trisomy of the 21st chromosome causes Down Syndrome...

. It is named after John Langdon Down
John Langdon Down
John Langdon Haydon Down was a British doctor best known for his description of a relatively common genetic disorder that is now called Down syndrome.-Education:...

, the British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 physician
Physician
A physician is a health care provider who practices the profession of medicine, which is concerned with promoting, maintaining or restoring human health through the study, diagnosis, and treatment of disease, injury and other physical and mental impairments...

 who described the syndrome
Syndrome
In medicine and psychology, a syndrome is the association of several clinically recognizable features, signs , symptoms , phenomena or characteristics that often occur together, so that the presence of one or more features alerts the physician to the possible presence of the others...

 in 1866. The condition was clinically described earlier in the 19th century by Jean Etienne Dominique Esquirol in 1838 and Edouard Seguin
Edouard Seguin
Édouard Séguin was a physician and educationist who was born in Clamecy, Nièvre. He is remembered for his work with children having cognitive impairments in France and the United States....

 in 1844. Down syndrome was identified as a chromosome 21 trisomy
Trisomy
A trisomy is a type of polysomy in which there are three copies, instead of the normal two, of a particular chromosome. A trisomy is a type of aneuploidy .-Description and causes:...

 by Dr. Jérôme Lejeune
Jérôme Lejeune
Servant of God Jérôme Jean Louis Marie Lejeune was a French Catholic pro-life paediatrician and geneticist, best known for his discovery of the link of diseases to chromosome abnormalities...

 in 1959. Down syndrome in a fetus can be identified through chorionic villus sampling
Chorionic villus sampling
Chorionic villus sampling , sometimes misspelled "chorionic villous sampling", is a form of prenatal diagnosis to determine chromosomal or genetic disorders in the fetus. It entails sampling of the chorionic villus and testing it...

 or amniocentesis
Amniocentesis
Amniocentesis is a medical procedure used in prenatal diagnosis of chromosomal abnormalities and fetal infections, in which a small amount of amniotic fluid, which contains fetal tissues, is sampled from the amnion or amniotic sac surrounding a developing fetus, and the fetal DNA is examined for...

 during pregnancy, or in a baby at birth.

Down syndrome is a chromosomal condition characterized by the presence of an extra copy of genetic material on the 21st chromosome
Chromosome 21 (human)
Chromosome 21 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. The trisomy of the 21st chromosome causes Down Syndrome...

, either in whole (trisomy
Trisomy
A trisomy is a type of polysomy in which there are three copies, instead of the normal two, of a particular chromosome. A trisomy is a type of aneuploidy .-Description and causes:...

 21) or part (such as due to translocations
Chromosomal translocation
In genetics, a chromosome translocation is a chromosome abnormality caused by rearrangement of parts between nonhomologous chromosomes. A gene fusion may be created when the translocation joins two otherwise separated genes, the occurrence of which is common in cancer. It is detected on...

). The effects and extent of the extra copy vary greatly among people, depending on genetic history, and pure chance. The incidence of Down syndrome is estimated at 1 per 733 births, although it is statistically more common with older parents due to increased mutagenic exposures upon some older parents' reproductive cells. Other factors may also play a role. Down syndrome occurs in all human populations, and analogous effects have been found in other species such as chimpanzees and mice.

Often Down syndrome is associated with some impairment of cognitive
Cognition
In science, cognition refers to mental processes. These processes include attention, remembering, producing and understanding language, solving problems, and making decisions. Cognition is studied in various disciplines such as psychology, philosophy, linguistics, and computer science...

 ability and physical growth
Child development
Child development stages describe theoretical milestones of child development. Many stage models of development have been proposed, used as working concepts and in some cases asserted as nativist theories....

, and a particular set of facial characteristics. Individuals with Down syndrome tend to have a lower-than-average cognitive ability, often ranging from mild to moderate disabilities. Many children with Down syndrome who have received family support, enrichment therapies, and tutoring have been known to graduate from high school and college, and enjoy employment in the work force. The average IQ of children with Down syndrome is around 50, compared to normal children with an IQ of 100. A small number have a severe to high degree of intellectual disability.

Individuals with Down syndrome may have some or all of the following physical characteristics: microgenia
Microgenia
Microgenia is the medical term for an unusually small or deformed chin.The contrasting condition, an enlarged chin, is called "macrogenia".-References:...

 (an abnormally small chin), an unusually round face, macroglossia
Macroglossia
Macroglossia is the medical term for unusual enlargement of the tongue. Severe enlargement of the tongue can cause cosmetic and functional difficulties including in speaking, eating, swallowing and sleeping.- Amyloid Disorders :...

 (protruding or oversized tongue), an almond shape to the eyes caused by an epicanthic fold of the eyelid, upslanting palpebral fissure
Palpebral fissure
Palpebral fissure is the anatomic name for the separation between the upper and lower eyelids. In adults, this measures about 10mm vertically and 30mm horizontally.It can be reduced in horizontal size by fetal alcohol syndrome and in Williams Syndrome...

s (the separation between the upper and lower eyelids), shorter limbs, a single transverse palmar crease (a single instead of a double crease across one or both palms), poor muscle tone
Hypotonia
Hypotonia is a state of low muscle tone , often involving reduced muscle strength. Hypotonia is not a specific medical disorder, but a potential manifestation of many different diseases and disorders that affect motor nerve control by the brain or muscle strength...

, and a larger than normal space between the big and second toes. Health concerns for individuals with Down syndrome include a higher risk for congenital heart defect
Congenital heart defect
A congenital heart defect is a defect in the structure of the heart and great vessels which is present at birth. Many types of heart defects exist, most of which either obstruct blood flow in the heart or vessels near it, or cause blood to flow through the heart in an abnormal pattern. Other...

s, gastroesophageal reflux disease
Gastroesophageal reflux disease
Gastroesophageal reflux disease , gastro-oesophageal reflux disease , gastric reflux disease, or acid reflux disease is chronic symptoms or mucosal damage caused by stomach acid coming up from the stomach into the esophagus...

, recurrent ear infections
Otitis
Otitis is a general term for inflammation or infection of the ear, in both humans and other animals.It is subdivided into the following:*Otitis externa, external otitis, or "swimmer's ear" involves the outer ear and ear canal. In external otitis, the ear hurts when touched or pulled.*Otitis media...

 that may lead to hearing loss, obstructive sleep apnea
Obstructive sleep apnea
Obstructive sleep apnea or obstructive sleep apnea syndrome is the most common type of sleep apnea and is caused by obstruction of the upper airway. It is characterized by repetitive pauses in breathing during sleep, despite the effort to breathe, and is usually associated with a reduction in...

, thyroid
Thyroid
The thyroid gland or simply, the thyroid , in vertebrate anatomy, is one of the largest endocrine glands. The thyroid gland is found in the neck, below the thyroid cartilage...

 dysfunctions, and obesity.

Early childhood intervention
Early Childhood Intervention
Early childhood intervention is a support system for children with developmental disabilities or delays and their families.The mission of Early Childhood Intervention is to assure that families who have children ages birth to three, with diagnosed disabilities, developmental delays or substantial...

, screening for common problems, medical treatment where indicated, a conducive family environment, and vocational training can improve the overall development of children with Down syndrome. Education and proper care will improve quality of life
Quality of life
The term quality of life is used to evaluate the general well-being of individuals and societies. The term is used in a wide range of contexts, including the fields of international development, healthcare, and politics. Quality of life should not be confused with the concept of standard of...

 significantly, despite genetic limitations.

History

English physician John Langdon Down
John Langdon Down
John Langdon Haydon Down was a British doctor best known for his description of a relatively common genetic disorder that is now called Down syndrome.-Education:...

 first characterized Down syndrome as a distinct form of mental disability in 1862, and in a more widely published report in 1866. Due to his perception that children with Down syndrome shared physical facial similarities (epicanthal folds) with those of Blumenbach's Mongolian race
Johann Friedrich Blumenbach
Johann Friedrich Blumenbach was a German physician, physiologist and anthropologist, one of the first to explore the study of mankind as an aspect of natural history, whose teachings in comparative anatomy were applied to classification of what he called human races, of which he determined...

, Down used the term mongoloid, derived from prevailing ethnic theory; while the term "mongoloid" (also "mongol" or "mongoloid idiot") continued to be used until the early 1970s, it is now considered to be pejorative (as well as inaccurate) and is no longer in common use.

By the 20th century, Down syndrome had become the most recognizable form of mental disability. Most individuals with Down syndrome were institutionalized, few of the associated medical problems were treated, and most died in infancy or early adult life. With the rise of the eugenics movement, 33 of the (then) 48 U.S. state
U.S. state
A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

s and several countries began programs of forced sterilization of individuals with Down syndrome and comparable degrees of disability. "Action T4
Action T4
Action T4 was the name used after World War II for Nazi Germany's eugenics-based "euthanasia" program during which physicians killed thousands of people who were "judged incurably sick, by critical medical examination"...

" in Nazi Germany
Nazi Germany
Nazi Germany , also known as the Third Reich , but officially called German Reich from 1933 to 1943 and Greater German Reich from 26 June 1943 onward, is the name commonly used to refer to the state of Germany from 1933 to 1945, when it was a totalitarian dictatorship ruled by...

 made public policy of a program of systematic murder. Court challenges, scientific advances and public revulsion led to discontinuation or repeal of such sterilization programs during the decades after World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

.

Until the middle of the 20th century, the cause of Down syndrome remained unknown. However, the presence in all races, the association with older maternal age, and the rarity of recurrence had been noticed. Standard medical texts assumed it was caused by a combination of inheritable factors that had not been identified. Other theories focused on injuries sustained during birth.

With the discovery of karyotype
Karyotype
A karyotype is the number and appearance of chromosomes in the nucleus of an eukaryotic cell. The term is also used for the complete set of chromosomes in a species, or an individual organism.p28...

 techniques in the 1950s, it became possible to identify abnormalities of chromosomal number or shape. In 1959, Jérôme Lejeune discovered that Down syndrome resulted from an extra chromosome. The extra chromosome was subsequently labeled as the 21st, and the condition as trisomy 21.

In 1961, 18 geneticists wrote to the editor of The Lancet
The Lancet
The Lancet is a weekly peer-reviewed general medical journal. It is one of the world's best known, oldest, and most respected general medical journals...

suggesting that Mongolian idiocy had "misleading connotations," had become "an embarrassing term," and should be changed. The Lancet supported Down's Syndrome. The World Health Organization
World Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...

 (WHO) officially dropped references to mongolism in 1965 after a request by the Mongolian delegate. However, almost 40 years later, the term ‘mongolism’ still appears in leading medical texts such as General and Systematic Pathology, 4th Edition, 2004, edited by Professor Sir James Underwood
James Underwood
Professor Sir James Underwood is a British pathologist who was awarded a knighthood for services to medicine in the 2005 New Year honours list.-Early life and education:...

. Advocacy groups adapted and parents groups welcomed the elimination of the Mongoloid label that had been a burden to their children. The first parents group in the United States, the Mongoloid Development Council, changed its name to the National Association for Down Syndrome in 1972.

In 1975, the United States National Institutes of Health
National Institutes of Health
The National Institutes of Health are an agency of the United States Department of Health and Human Services and are the primary agency of the United States government responsible for biomedical and health-related research. Its science and engineering counterpart is the National Science Foundation...

 convened a conference to standardize the nomenclature of malformations. They recommended eliminating the possessive form: "The possessive use of an eponym should be discontinued, since the author neither had nor owned the condition." Although both the possessive and non-possessive forms are used in the general population, Down syndrome is the accepted term among professionals in the U.S., Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

 and other countries; Down's syndrome is still used in the UK and other areas.

Neoteny

The signs
Medical sign
A medical sign is an objective indication of some medical fact or characteristic that may be detected by a physician during a physical examination of a patient....

 and symptom
Symptom
A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality...

s Down syndrome are characterized by the neotenization
Neoteny
Neoteny , also called juvenilization , is one of the two ways by which paedomorphism can arise. Paedomorphism is the retention by adults of traits previously seen only in juveniles, and is a subject studied in the field of developmental biology. In neoteny, the physiological development of an...

 of the brain and body to the fetal state. Down syndrome is characterized by decelerated maturation (neoteny), incomplete morphogenesis (vestigia) and atavism
Atavism
Atavism is the tendency to revert to ancestral type. In biology, an atavism is an evolutionary throwback, such as traits reappearing which had disappeared generations before. Atavisms can occur in several ways...

s. Dr. Weihs considers Down syndrome to be a condition of "neoteny" that makes people "like a baby."

Down syndrome can result from several different genetic mechanisms. This results in a wide variability in individual due to complex gene and environment interactions. Prior to birth, it is not possible to predict the symptoms that an individual with Down syndrome will develop.

Physical characteristics

Individuals with Down syndrome may have some or all of the following physical characteristics: microgenia
Microgenia
Microgenia is the medical term for an unusually small or deformed chin.The contrasting condition, an enlarged chin, is called "macrogenia".-References:...

 (abnormally small chin), oblique eye fissures with epicanthic skin folds on the inner corner of the eyes (formerly known as a mongoloid fold), muscle hypotonia
Hypotonia
Hypotonia is a state of low muscle tone , often involving reduced muscle strength. Hypotonia is not a specific medical disorder, but a potential manifestation of many different diseases and disorders that affect motor nerve control by the brain or muscle strength...

 (poor muscle tone), a flat nasal bridge, a single palmar fold, a protruding tongue (due to small oral cavity, and an enlarged tongue near the tonsils) or macroglossia
Macroglossia
Macroglossia is the medical term for unusual enlargement of the tongue. Severe enlargement of the tongue can cause cosmetic and functional difficulties including in speaking, eating, swallowing and sleeping.- Amyloid Disorders :...

, "face is flat and broad", a short neck, white spots on the iris
Iris (anatomy)
The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...

 known as Brushfield spots
Brushfield spots
Brushfield spots are small white or grayish/brown spots on the periphery of the iris in the human eye due to aggregation of connective tissue, a normal iris element. The spots are named after the physician, Thomas Brushfield, who first described them in his 1924 M.D...

, excessive joint laxity including atlanto-axial instability, excessive space between large toe
Hallux
In tetrapods, the hallux is the innermost toe of the foot. Despite its name it may not be the longest toe on the foot of some individuals...

 and second toe, a single flexion
Flexion
In anatomy, flexion is a position that is made possible by the joint angle decreasing. The skeletal and muscular systems work together to move the joint into a "flexed" position. For example the elbow is flexed when the hand is brought closer to the shoulder...

 furrow of the fifth finger, a higher number of ulnar loop dermatoglyphs
Dermatoglyphics
Dermatoglyphics is the scientific study of fingerprints. The term was coined by Dr. Harold Cummins, the father of American fingerprint analysis, even though the process of fingerprint identification had already been in use for several hundred years. All primates have ridged skin...

 and short fingers.

Growth parameters such as height, weight, and head circumference are smaller in children with DS than with typical individuals of the same age. Adults with DS tend to have short stature
Short stature
Short stature refers to a height of a human being which is below expected. Shortness is a vague term without a precise definition and with significant relativity to context...

 and bowed legs—the average height for men is 5 feet 1 inch (154 cm) and for women is 4 feet 9 inches (144 cm). Individuals with DS are also at increased risk for obesity as they age and tend to be "round in shape".
Characteristics Percentage Characteristics Percentage
mental retardation 100% small teeth 60%
stunted growth 100% flattened nose 60%
atypical fingerprints 90% clinodactyly
Clinodactyly
-References:...

52%
separation of the abdominal muscles 80% umbilical hernia
Umbilical hernia
Congenital umbilical hernia is a congenital malformation, common in infants of African descent. Among adults, it is three times more common in women than in men; among children, the ratio is roughly equal...

51%
flexible ligaments 80% short neck 50%
hypotonia
Hypotonia
Hypotonia is a state of low muscle tone , often involving reduced muscle strength. Hypotonia is not a specific medical disorder, but a potential manifestation of many different diseases and disorders that affect motor nerve control by the brain or muscle strength...

80% shortened hands 50%
brachycephaly
Brachycephaly
Brachycephaly, also known as flat head syndrome, is a type of cephalic disorder. This can result from premature fusion of the coronal sutures or from external deformation . The coronal suture is the fibrous joint that unites the frontal bone with the two parietal bones of the skull. The parietal...

75% congenital heart disease
Heart disease
Heart disease, cardiac disease or cardiopathy is an umbrella term for a variety of diseases affecting the heart. , it is the leading cause of death in the United States, England, Canada and Wales, accounting for 25.4% of the total deaths in the United States.-Types:-Coronary heart disease:Coronary...

45%
smaller genitalia 75% single transverse palmar crease 45%
eyelid crease 75% Macroglossia
Macroglossia
Macroglossia is the medical term for unusual enlargement of the tongue. Severe enlargement of the tongue can cause cosmetic and functional difficulties including in speaking, eating, swallowing and sleeping.- Amyloid Disorders :...

 (larger tongue)
43%
shortened extremities 70% epicanthal fold
Epicanthal fold
An epicanthic fold, epicanthal fold, or epicanthus is a skin fold of the upper eyelid, covering the inner corner of the eye....

42%
oval palate
Palate
The palate is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but, in most other tetrapods, the oral and nasal cavities are not truly separate. The palate is divided into two parts, the anterior...

69% Strabismus
Strabismus
Strabismus is a condition in which the eyes are not properly aligned with each other. It typically involves a lack of coordination between the extraocular muscles, which prevents bringing the gaze of each eye to the same point in space and preventing proper binocular vision, which may adversely...

40%
low-set and rounded ear 60% Brushfield spots
Brushfield spots
Brushfield spots are small white or grayish/brown spots on the periphery of the iris in the human eye due to aggregation of connective tissue, a normal iris element. The spots are named after the physician, Thomas Brushfield, who first described them in his 1924 M.D...

 (iris
Iris (anatomy)
The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...

)
35%

Mental characteristics

Most individuals with Down syndrome have intellectual disability
Intellectual disability
Intellectual disability is a broad concept encompassing various intellectual deficits, including mental retardation , deficits too mild to properly qualify as MR, various specific conditions , and problems acquired later in life through acquired brain injuries or neurodegenerative diseases like...

 in the mild (IQ 50–70) to moderate (IQ 35–50) range, with individuals having Mosaic Down syndrome typically 10–30 points higher.

Dr. Weihs notes the mental qualities of people with Down syndrome to be "unsexual," "playful," "affectionate," "mischievous" and "imitative".

Language skills show a difference between understanding speech and expressing speech, and commonly individuals with Down syndrome have a speech delay
Speech delay
Speech delay, also known as alalia, refers to a delay in the development or use of the mechanisms that produce speech. Speech, as distinct from language, refers to the actual process of making sounds, using such organs and structures as the lungs, vocal cords, mouth, tongue, teeth, etc...

. Fine motor skill
Fine motor skill
Fine motor skills are the coordination of small muscle movements which occur e.g., in the fingers, usually in coordination with the eyes. In application to motor skills of hands the term dexterity is commonly used....

s are delayed and often lag behind gross motor skill
Gross motor skill
Gross motor skills are the abilities usually acquired during infancy and early childhood as part of a child's motor development. By the time they reach two years of age, almost all children are able to stand up, walk and run, walk up stairs, etc...

s and can interfere with cognitive development. Effects of the condition on the development of gross motor skills are quite variable. Some children will begin walking at around 2 years of age, while others will not walk until age 4. Physical therapy, and/or participation in a program of adapted physical education (APE), may promote enhanced development of gross motor skills in Down syndrome children.
Criticism of IQ tests for people with Down syndrome

Chris Borthwick claims parents and educators have low expectations for people with Down syndrome which depresses tested IQ of people with Down syndrome. Also, he claims that IQ tests do not take into account the hearing impairment 62% of people with Down syndrome face or the vision impairment 77% of people with Down syndrome face. These physical disabilities would slow the test-taking performance of a person with Down syndrome, resulting in a lower IQ score.

Genetics

Recently, researchers have created transgenic mice with most of human chromosome 21 (in addition to the normal mouse chromosomes). The extra chromosomal material can come about in several distinct ways. A typical human karyotype is designated as 46,XX or 46,XY, indicating 46 chromosomes with an XX arrangement typical of females and 46 chromosomes with an XY arrangement typical of males.

Trisomy 21

Trisomy 21 (47,XX,+21) is caused by a meiotic
Meiosis
Meiosis is a special type of cell division necessary for sexual reproduction. The cells produced by meiosis are gametes or spores. The animals' gametes are called sperm and egg cells....

 nondisjunction
Nondisjunction
Nondisjunction is the failure of chromosome pairs to separate properly during meiosis stage 1 or stage 2. This could arise from a failure of homologous chromosomes to separate in meiosis I, or the failure of sister chromatids to separate during meiosis II or mitosis. The result of this error is a...

 event. With nondisjunction, a gamete
Gamete
A gamete is a cell that fuses with another cell during fertilization in organisms that reproduce sexually...

 (i.e., a sperm or egg cell) is produced with an extra copy of chromosome 21; the gamete thus has 24 chromosomes. When combined with a normal gamete from the other parent, the embryo
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...

 now has 47 chromosomes, with three copies of chromosome 21. Trisomy 21 is the cause of approximately 95% of observed Down syndromes, with 88% coming from nondisjunction in the maternal gamete and 8% coming from nondisjunction in the paternal gamete. The actual Down syndrome "critical region" encompasses chromosome bands 21q22.1-q22.3.

Mosaicism

Trisomy 21 is usually caused by nondisjunction in the gametes prior to conception, and all cells in the body are affected. However, when some of the cells in the body are normal and other cells have trisomy 21, it is called mosaic
Mosaic (genetics)
In genetic medicine, a mosaic or mosaicism denotes the presence of two populations of cells with different genotypes in one individual who has developed from a single fertilized egg...

 Down syndrome (46,XX/47,XX,+21). This can occur in one of two ways: a nondisjunction event during an early cell division in a normal embryo leads to a fraction of the cells with trisomy 21; or a Down syndrome embryo undergoes nondisjunction and some of the cells in the embryo revert to the normal chromosomal arrangement. There is considerable variability in the fraction of trisomy 21, both as a whole and among tissues. This is the cause of 1–2% of the observed Down syndromes.

Robertsonian translocation

The extra chromosome 21 material that causes Down syndrome may be due to a Robertsonian translocation
Robertsonian translocation
Robertsonian translocation is a common form of chromosomal rearrangement that in humans occurs in the five acrocentric chromosome pairs, namely 13, 14, 15, 21, and 22. Other translocations occur but do not lead to a viable fetus. They are named after the American biologist William Rees Brebner...

 in the karyotype of one of the parents. In this case, the long arm of chromosome 21 is attached to another chromosome, often chromosome 14
Chromosome 14 (human)
rightChromosome14 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 14 spans about 109 million base pairs and represents between 3 and 3.5% of the total DNA in cells....

 [45,XX,der(14;21)(q10;q10)]. A person with such a translocation is phenotypically normal. During reproduction, normal disjunctions leading to gametes have a significant chance of creating a gamete with an extra chromosome 21, producing a child with Down syndrome. Translocation Down syndrome is often referred to as familial Down syndrome. It is the cause of 2–3% of observed cases of Down syndrome. It does not show the maternal age effect, and is just as likely to have come from fathers as mothers.

Duplication of a portion of chromosome 21

Rarely, a region of chromosome 21 will undergo a duplication event. This will lead to extra copies of some, but not all, of the genes on chromosome 21 (46,XX, dup(21q)). If the duplicated region has genes that are responsible for Down syndrome physical and mental characteristics, such individuals will show those characteristics. This cause is rare and no rate estimates are available.

Epidemiology

The incidence of Down syndrome is estimated at one per 800 to one per 1000 births. In 2006, the Centers for Disease Control and Prevention
Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention are a United States federal agency under the Department of Health and Human Services headquartered in Druid Hills, unincorporated DeKalb County, Georgia, in Greater Atlanta...

 estimated the rate as one per 733 live births in the United States (5429 new cases per year). Approximately 95% of these are trisomy 21. Down syndrome occurs in all ethnic groups and among all economic classes.

Maternal age influences the chances of conceiving a baby with Down syndrome. At maternal age 20 to 24, the probability is one in 1562; at age 35 to 39 the probability is one in 214, and above age 45 the probability is one in 19. Although the probability increases with maternal age, 80% of children with Down syndrome are born to women under the age of 35, reflecting the overall fertility of that age group. Recent data also suggest that paternal age
Paternal age effect
The paternal age effect can refer to the statistical relationships of: a man's age to sperm and semen abnormalities; a man's age to his fertility; a man's age to adverse pregnancy outcomes in his female partner ; a father's age at the birth of his offspring on the probability of an adverse...

, especially beyond 42, also increases the risk of Down syndrome manifesting.

Current research (as of 2008) has shown that Down syndrome is due to a random event during the formation of sex cells or pregnancy. There has been no evidence that it is due to parental behavior (other than age) or environmental factors.

Screening

Pregnant women can be screened for various complications during pregnancy. Many standard prenatal screens can discover Down syndrome. Genetic counseling
Genetic counseling
Genetic counseling or traveling is the process by which patients or relatives, at risk of an inherited disorder, are advised of the consequences and nature of the disorder, the probability of developing or transmitting it, and the options open to them in management and family planning...

 along with genetic testing
Genetic testing
Genetic testing is among the newest and most sophisticated of techniques used to test for genetic disorders which involves direct examination of the DNA molecule itself. Other genetic tests include biochemical tests for such gene products as enzymes and other proteins and for microscopic...

, such as amniocentesis
Amniocentesis
Amniocentesis is a medical procedure used in prenatal diagnosis of chromosomal abnormalities and fetal infections, in which a small amount of amniotic fluid, which contains fetal tissues, is sampled from the amnion or amniotic sac surrounding a developing fetus, and the fetal DNA is examined for...

, chorionic villus sampling
Chorionic villus sampling
Chorionic villus sampling , sometimes misspelled "chorionic villous sampling", is a form of prenatal diagnosis to determine chromosomal or genetic disorders in the fetus. It entails sampling of the chorionic villus and testing it...

 (CVS), or percutaneous umbilical cord blood sampling
Percutaneous umbilical cord blood sampling
Percutaneous umbilical cord blood sampling , also called cordocentesis, is a diagnostic genetic test that examines blood from the fetal umbilical cord to detect fetal abnormalities. PUBS provides a means of rapid chromosome analysis and is useful when information cannot be obtained through...

 (PUBS) are usually offered to families who may have an increased chance of having a child with Down syndrome, or where normal prenatal exams indicate possible problems. In the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, ACOG guidelines recommend that non-invasive screening and invasive testing be offered to all women, regardless of their age, and most likely all physicians currently follow these guidelines. However, some insurance plans will only reimburse invasive testing if a woman is >34 years old or if she has received a high-risk score from a non-invasive screening test.

Amniocentesis and CVS are considered invasive procedures, in that they involve inserting instruments into the uterus, and therefore carry a small risk of causing fetal injury or miscarriage. The risks of miscarriage for CVS and amniocentesis are often quoted as 1% and 0.5% respectively. There are several common non-invasive screens that can indicate a fetus with Down syndrome. These are normally performed in the late first trimester or early second trimester. Due to the nature of screens, each has a significant chance of a false positive
Type I and type II errors
In statistical test theory the notion of statistical error is an integral part of hypothesis testing. The test requires an unambiguous statement of a null hypothesis, which usually corresponds to a default "state of nature", for example "this person is healthy", "this accused is not guilty" or...

, suggesting a fetus with Down syndrome when, in fact, the fetus does not have this genetic condition. Screen positives must be verified before a Down syndrome diagnosis is made. Common screening procedures for Down syndrome are given in Table 1.
Table 1: First and second trimester Down syndrome screens
Screen When performed (weeks gestation
Gestation
Gestation is the carrying of an embryo or fetus inside a female viviparous animal. Mammals during pregnancy can have one or more gestations at the same time ....

)
Detection rate False positive rate Description
Quad screen 15–20 81% 5% This test measures the maternal serum alpha feto protein (a fetal liver protein), estriol (a pregnancy hormone), human chorionic gonadotropin (hCG, a pregnancy hormone), and inhibin-Alpha (INHA).
Nuchal translucency/free beta/PAPPA screen (aka "1st Trimester Combined Test") 10–13.5 85% 5% Uses ultrasound
Ultrasound
Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...

 to measure Nuchal Translucency in addition to the freeBeta hCG and PAPPA (pregnancy-associated plasma protein A
Pregnancy-associated plasma protein A
Pregnancy-associated plasma protein A, pappalysin 1, also known as PAPPA, is a protein used in screening tests for Down syndrome.This gene encodes a secreted metalloproteinase which cleaves insulin-like growth factor binding proteins . It is thought to be involved in local proliferative processes...

). NIH has confirmed that this first trimester test is more accurate than second trimester screening methods. Performing an NT ultrasound requires considerable skill; a Combined test may be less accurate if there is operator error, resulting in a lower-than-advertised sensitivity and higher false-positive rate, possibly in the 5–10% range.
Integrated test 10-13.5 and 15–20 95% 5% The integrated test uses measurements from both the 1st trimester combined test and the 2nd trimester quad test to yield a more accurate screening result. Because all of these tests are dependent on accurate calculation of the gestational age of the fetus, the real-world false-positive rate is >5% and may be closer to 7.5%.


Even with the best non-invasive screens, the detection rate is 90–95% and the rate of false positive is 2–5%. Inaccuracies can be caused by undetected multiple fetuses (very rare with the ultrasound tests), incorrect date of pregnancy, or normal variation in the proteins.

Confirmation of screen positive is normally accomplished with amniocentesis or chorionic villus sampling (CVS). Amniocentesis is an invasive procedure and involves taking amniotic fluid
Amniotic fluid
Amniotic fluid or liquor amnii is the nourishing and protecting liquid contained by the amniotic sac of a pregnant woman.- Development of amniotic fluid :...

 from the amniotic sac and identifying fetal cells. The lab work can take several weeks but will detect over 99.8% of all numerical chromosomal problems with a very low false positive rate.

A non-invasive prenatal test, MaterniT21, detected Down syndrome based on fetal DNA in a sample of the mother's blood in 209 of 212 cases (98.6%). The International Society for Prenatal Diagnosis finds that this is an advanced screening test which may be of use, in conjunction with genetic counseling, in high-risk cases based upon existing screening strategies. While effective in the diagnosis of Down syndrome, it cannot assess other conditions which can be detected by invasive testing..

Abortion rates

A 2002 literature review of elective abortion
Abortion
Abortion is defined as the termination of pregnancy by the removal or expulsion from the uterus of a fetus or embryo prior to viability. An abortion can occur spontaneously, in which case it is usually called a miscarriage, or it can be purposely induced...

 rates found that 91–93% of pregnancies in the United Kingdom and Europe with a diagnosis of Down syndrome were terminated. Data from the National Down Syndrome Cytogenetic Register in the United Kingdom indicates that from 1989 to 2006 the proportion of women choosing to terminate a pregnancy following prenatal diagnosis of Down syndrome has remained constant at around 92%.

In the United States a number of studies have examined the abortion rate of fetuses with Down syndrome. Three studies estimated the termination rates at 95%, 98%, and 87% respectively.

Ethical issues

Medical ethicist Ronald Green argues that parents have an obligation to avoid 'genetic harm' to their offspring, and Claire Rayner
Claire Rayner
Claire Berenice Rayner OBE was an English nurse, journalist, broadcaster and novelist, best known for her role for many years as an agony aunt.-Early life:...

, then a patron of the Down's Syndrome Association, defended testing and abortion saying "The hard facts are that it is costly in terms of human effort, compassion, energy, and finite resources such as money, to care for individuals with handicaps... People who are not yet parents should ask themselves if they have the right to inflict such burdens on others, however willing they are themselves to take their share of the burden in the beginning."

Some physicians and ethicists are concerned about the ethical ramifications of the high abortion rate for this condition. Conservative commentator George Will
George Will
George Frederick Will is an American newspaper columnist, journalist, and author. He is a Pulitzer Prize-winner best known for his conservative commentary on politics...

 called it "eugenics
Eugenics
Eugenics is the "applied science or the bio-social movement which advocates the use of practices aimed at improving the genetic composition of a population", usually referring to human populations. The origins of the concept of eugenics began with certain interpretations of Mendelian inheritance,...

 by abortion". British peer Lord Rix stated that "alas, the birth of a child with Down's syndrome is still considered by many to be an utter tragedy" and that the "ghost of the biologist Sir Francis Galton, who founded the eugenics movement in 1885, still stalks the corridors of many a teaching hospital
Teaching hospital
A teaching hospital is a hospital that provides clinical education and training to future and current doctors, nurses, and other health professionals, in addition to delivering medical care to patients...

". Doctor David Mortimer has argued in Ethics & Medicine that "Down's syndrome infants have long been disparaged by some doctors and government bean counters." Some members of the disability rights movement "believe that public support for prenatal diagnosis and abortion based on disability contravenes the movement's basic philosophy and goals." Peter Singer
Peter Singer
Peter Albert David Singer is an Australian philosopher who is the Ira W. DeCamp Professor of Bioethics at Princeton University and Laureate Professor at the Centre for Applied Philosophy and Public Ethics at the University of Melbourne...

 argued that "neither haemophilia nor Down's syndrome is so crippling as to make life not worth living from the inner perspective of the person with the condition. To abort a fetus with one of these disabilities, intending to have another child who will not be disabled, is to treat fetuses as interchangeable or replaceable. If the mother has previously decided to have a certain number of children, say two, then what she is doing, in effect, is rejecting one potential child in favour of another. She could, in defence of her actions, say: the loss of life of the aborted fetus is outweighed by the gain of a better life for the normal child who will be conceived only if the disabled one dies."

Health

Individuals with Down syndrome have a higher risk for many conditions. The medical consequences of the extra genetic material in Down syndrome are highly variable and may affect the function of any organ system or bodily process. Some problems are present at birth, such as certain heart malformations. Others become apparent over time, such as epilepsy.

Congenital heart disease

The incidence
Incidence (epidemiology)
Incidence is a measure of the risk of developing some new condition within a specified period of time. Although sometimes loosely expressed simply as the number of new cases during some time period, it is better expressed as a proportion or a rate with a denominator.Incidence proportion is the...

 of congenital heart disease in children with Down syndrome is up to 50%. An atrioventricular septal defect
Atrioventricular septal defect
Atrioventricular septal defect or atrioventricular canal defect , previously known as "common atrioventricular canal" or "endocardial cushion defect", is characterized by a deficiency of the atrioventricular septum of the heart...

 also known as endocardial cushion defect is the most common form with up to 40% of patients affected. This is closely followed by ventricular septal defect
Ventricular septal defect
A ventricular septal defect is a defect in the ventricular septum, the wall dividing the left and right ventricles of the heart.The ventricular septum consists of an inferior muscular and superior membranous portion and is extensively innervated with conducting cardiomyocytes.The membranous...

 that affects approximately 30% of patients.

Malignancies

Hematologic malignancies such as leukemia are more common in children with DS. In particular, the risk for acute lymphoblastic leukemia
Acute lymphoblastic leukemia
Acute lymphoblastic leukemia is a form of leukemia, or cancer of the white blood cells characterized by excess lymphoblasts.Malignant, immature white blood cells continuously multiply and are overproduced in the bone marrow. ALL causes damage and death by crowding out normal cells in the bone...

 is at least 10 times more common in DS and for the megakaryoblastic form of acute myelogenous leukemia is at least 50 times more common in DS. Transient leukemia is a form of leukemia that is rare in individuals without DS but affects up to 20 percent of newborns with DS. This form of leukemia is typically benign and resolves on its own over several months, though it can lead to other serious illnesses. In contrast to hematologic malignancies, solid tumor malignancies are less common in DS, possibly due to increased numbers of tumor suppressor gene
Tumor suppressor gene
A tumor suppressor gene, or anti-oncogene, is a gene that protects a cell from one step on the path to cancer. When this gene is mutated to cause a loss or reduction in its function, the cell can progress to cancer, usually in combination with other genetic changes.-Two-hit hypothesis:Unlike...

s contained in the extra genetic material.

Decreased incidence of many cancer types

Health benefits of Down syndrome include greatly reduced incidence of many common malignancies except leukemia and testicular cancer—although it is, as yet, unclear whether the reduced incidence of various fatal cancers among people with Down syndrome is as a direct result of tumor-suppressor genes on chromosome 21, because of reduced exposure to environmental factor
Environmental factor
Environmental factor or ecological factor or ecofactor is any factor, abiotic or biotic, that influences living organisms.- Environmental factors inducing diseases :...

s that contribute to cancer risk, or some other as-yet unspecified factor. In addition to a reduced risk of most kinds of cancer, people with Down syndrome also have a much lower risk of hardening of the arteries
Atherosclerosis
Atherosclerosis is a condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol...

 and diabetic retinopathy
Diabetic retinopathy
Diabetic retinopathy is retinopathy caused by complications of diabetes mellitus, which can eventually lead to blindness....

.

Thyroid disorders

Individuals with DS are at increased risk for dysfunction of the thyroid gland, an organ that helps control metabolism
Metabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...

. Low thyroid (hypothyroidism
Hypothyroidism
Hypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone.Iodine deficiency is the most common cause of hypothyroidism worldwide but it can be caused by other causes such as several conditions of the thyroid gland or, less commonly, the pituitary gland or...

) is most common, occurring in almost a third of those with DS. This can be due to absence of the thyroid at birth (congenital hypothyroidism
Congenital hypothyroidism
Congenital hypothyroidism is a condition of thyroid hormone deficiency present at birth. Approximately 1 in 4000 newborn infants has a severe deficiency of thyroid function, while even more have mild or partial degrees. If untreated for several months after birth, severe congenital hypothyroidism...

) or due to attack on the thyroid by the immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...

.

Gastrointestinal

Down syndrome increases the risk of Hirschsprung's disease
Hirschsprung's disease
Hirschsprung's disease , or congenital aganglionic megacolon is a serious medical problem where the enteric nervous system is missing from the end of the bowel. The enteric nervous system is a complex network of neurons and glia that controls most aspects of intestinal function...

, in which the nerve cells that control the function of parts of the colon
Colon (anatomy)
The colon is the last part of the digestive system in most vertebrates; it extracts water and salt from solid wastes before they are eliminated from the body, and is the site in which flora-aided fermentation of unabsorbed material occurs. Unlike the small intestine, the colon does not play a...

 are not present. This results in severe constipation. Other congenital anomalies occurring more frequently in DS include duodenal atresia
Duodenal atresia
Duodenal atresia is the congenital absence or complete closure of a portion of the lumen of the duodenum. -Associated conditions:Approximately 20–40% of all infants with duodenal atresia have Down syndrome....

, annular pancreas
Annular pancreas
Annular pancreas is a rare condition in which the second part of the duodenum is surrounded by a ring of pancreatic tissue continuous with the head of the pancreas. This portion of the pancreas can constrict the duodenum and block or impair the flow of food to the rest of the intestines. It is...

, and imperforate anus
Imperforate anus
An imperforate anus or anal atresia is a birth defect in which the rectum is malformed. Its cause is unknown.-Features:There are several forms of imperforate anus:* A low lesion, in which the colon remains close to the skin...

. Gastroesophageal reflux disease
Gastroesophageal reflux disease
Gastroesophageal reflux disease , gastro-oesophageal reflux disease , gastric reflux disease, or acid reflux disease is chronic symptoms or mucosal damage caused by stomach acid coming up from the stomach into the esophagus...

 and celiac disease are also more common among people with DS.

Infertility

There is infertility
Infertility
Infertility primarily refers to the biological inability of a person to contribute to conception. Infertility may also refer to the state of a woman who is unable to carry a pregnancy to full term...

 among both males and females with Down syndrome; males are usually unable to father children, while females demonstrate significantly lower rates of conception relative to unaffected individuals. Women with DS are less fertile and often have difficulties with miscarriage
Miscarriage
Miscarriage or spontaneous abortion is the spontaneous end of a pregnancy at a stage where the embryo or fetus is incapable of surviving independently, generally defined in humans at prior to 20 weeks of gestation...

, premature birth
Premature birth
In humans preterm birth refers to the birth of a baby of less than 37 weeks gestational age. The cause for preterm birth is in many situations elusive and unknown; many factors appear to be associated with the development of preterm birth, making the reduction of preterm birth a challenging...

, and difficult labor
Childbirth
Childbirth is the culmination of a human pregnancy or gestation period with the birth of one or more newborn infants from a woman's uterus...

. Without preimplantation genetic diagnosis
Preimplantation genetic diagnosis
In medicine and genetics pre-implantation genetic diagnosis refers to procedures that are performed on embryos prior to implantation, sometimes even on oocytes prior to fertilization. PGD is considered another way to prenatal diagnosis...

, approximately half of the offspring of someone with Down syndrome also have the syndrome themselves. Men with DS are almost uniformly infertile
Infertility
Infertility primarily refers to the biological inability of a person to contribute to conception. Infertility may also refer to the state of a woman who is unable to carry a pregnancy to full term...

, exhibiting defects in spermatogenesis
Spermatogenesis
Spermatogenesis is the process by which male primary germ cells undergo division, and produce a number of cells termed spermatogonia, from which the primary spermatocytes are derived. Each primary spermatocyte divides into two secondary spermatocytes, and each secondary spermatocyte into two...

. There have been only three recorded instances of males with Down syndrome fathering children.

Neurology

Children and adults with DS are at increased risk for developing epilepsy
Epilepsy
Epilepsy is a common chronic neurological disorder characterized by seizures. These seizures are transient signs and/or symptoms of abnormal, excessive or hypersynchronous neuronal activity in the brain.About 50 million people worldwide have epilepsy, and nearly two out of every three new cases...

. The risk for Alzheimer's disease
Alzheimer's disease
Alzheimer's disease also known in medical literature as Alzheimer disease is the most common form of dementia. There is no cure for the disease, which worsens as it progresses, and eventually leads to death...

 is increased in individuals with DS, with 10–25% of individuals with DS showing signs of AD before age 50, up to 50% with clinical symptoms in the sixth decade, and up to 75% in the 7th decade. This sharp increase in the incidence and prevalence of dementia may be one of the factors driving the decreased life expectancy of persons with Down syndrome.

Ophthalmology and otolaryngology

Eye disorders are more common in people with DS. Almost half have strabismus
Strabismus
Strabismus is a condition in which the eyes are not properly aligned with each other. It typically involves a lack of coordination between the extraocular muscles, which prevents bringing the gaze of each eye to the same point in space and preventing proper binocular vision, which may adversely...

, in which the two eyes do not move in tandem. Refractive errors requiring glasses or contacts are also common. Cataract
Cataract
A cataract is a clouding that develops in the crystalline lens of the eye or in its envelope, varying in degree from slight to complete opacity and obstructing the passage of light...

s (opacity of the lens), keratoconus
Keratoconus
Keratoconus , is a degenerative disorder of the eye in which structural changes within the cornea cause it to thin and change to a more conical shape than its normal gradual curve....

 (thin, cone-shaped corneas), and glaucoma
Glaucoma
Glaucoma is an eye disorder in which the optic nerve suffers damage, permanently damaging vision in the affected eye and progressing to complete blindness if untreated. It is often, but not always, associated with increased pressure of the fluid in the eye...

 (increased eye pressures) are also more common in DS. Brushfield spots
Brushfield spots
Brushfield spots are small white or grayish/brown spots on the periphery of the iris in the human eye due to aggregation of connective tissue, a normal iris element. The spots are named after the physician, Thomas Brushfield, who first described them in his 1924 M.D...

 (small white or grayish/brown spots on the periphery of the iris
Iris (anatomy)
The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...

) may be present.

Hearing loss

In the past, prior to current treatment, there was a 38–78% incidence of hearing loss in children with Down syndrome. Fortunately, with aggressive, meticulous and compulsive diagnosis and treatment of chronic ear disease (e.g. otitis media
Otitis media
Otitis media is inflammation of the middle ear, or a middle ear infection.It occurs in the area between the tympanic membrane and the inner ear, including a duct known as the eustachian tube. It is one of the two categories of ear inflammation that can underlie what is commonly called an earache,...

, also known as Glue-ear) in children with Down syndrome, approximately 98% of the children have normal hearing levels.

However, more recent studies show that hearing impairment and otological problems are still found in 38-90% of children with Down syndrome compared to 2.5% for normal children.

The elevated occurrence of hearing loss for individuals with Down is not surprising. Every component in the auditory system is potentially adversely affected by Down syndrome. Problems may include:
  • stenosis of the ear canal
    Ear canal
    The ear canal , is a tube running from the outer ear to the middle ear. The human ear canal extends from the pinna to the eardrum and is about 35 mm in length and 5 to 10 mm in diameter....

  • malformation of the malleus
    Malleus
    The malleus or hammer is a hammer-shaped small bone or ossicle of the middle ear which connects with the incus and is attached to the inner surface of the eardrum...

    , incus
    Incus
    The incus or anvil is the anvil-shaped small bone or ossicle in themiddle ear. It connects the malleus to the stapes. It was first described by Alessandro Achillini of Bologna.The incus transmits sound vibrations from the malleus to the stapes....

    , and stapes
  • shortened or narrow cochlea
    Cochlea
    The cochlea is the auditory portion of the inner ear. It is a spiral-shaped cavity in the bony labyrinth, making 2.5 turns around its axis, the modiolus....

  • neural transmission rates that are accelerated (at the level or brainstem) or delayed (at the level of the cortex)
  • weak immune system leading to increased middle ear
    Middle ear
    The middle ear is the portion of the ear internal to the eardrum, and external to the oval window of the cochlea. The mammalian middle ear contains three ossicles, which couple vibration of the eardrum into waves in the fluid and membranes of the inner ear. The hollow space of the middle ear has...

     pathology


Otitis media with effusion is the most common cause of hearing loss in Down children, the infections start at birth and continue throughout the children’s lives. The ear infections are mainly associated with Eustachian tube
Eustachian tube
The Eustachian tube is a tube that links the nasopharynx to the middle ear. It is a part of the middle ear. In adult humans the Eustachian tube is approximately 35 mm long. It is named after the sixteenth-century anatomist Bartolomeo Eustachi...

 dysfunction due to alterations in the skull base. However, excessive accumulation of wax can also cause obstruction of the outer ear canal as it is often narrowed in children with Down syndrome. Middle ear problems account for 83% of hearing loss in children with Down syndrome. The degree of hearing loss varies but even a mild degree can have major consequences on speech perception, language acquisition, development and academic achievement if not detected in time and corrected.

Early intervention to treat the hearing loss and adapted education is useful to facilitate the development of children with Down syndrome, especially during the preschool period. For adults, social independence depends largely on the ability to complete tasks without assistance, the willingness to separate emotionally from parents and access to personal recreational activities. Given this background it is always important to rule out hearing loss as a contributing factor in social and mental deterioration.

Other complications

Instability of the atlanto-axial joint
Atlanto-axial joint
The Atlanto-axial joint is of a complicated nature. It consists of no fewer than four distinct joints....

 occurs in approximately 15% of people with DS, probably due to ligamental laxity. It may lead to the neurologic symptoms of spinal cord compression
Spinal cord compression
Spinal cord compression develops when the spinal cord is compressed by bone fragments from a vertebral fracture, a tumor, abscess, ruptured intervertebral disc or other lesion...

. Periodic screening, with cervical x-rays, is recommended to identify this condition.

Other serious illnesses include immune deficiencies.

Prognosis

The above factors can contribute to a shorter life expectancy for people with Down syndrome. One study, carried out in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 in 2002, showed an average lifespan of 49 years, with considerable variations between different ethnic and socio-economic groups. However, in recent decades, the life expectancy among persons with Down syndrome has increased significantly up from 25 years in 1980. The causes of death have also changed, with chronic neurodegenerative diseases becoming more common as the population ages. Most people with Down syndrome who live into their 40s and 50s begin to suffer from an Alzheimer's disease-like dementia.

Management

Treatment of individuals with Down syndrome depends on the particular manifestations of the condition. For instance, individuals with congenital heart disease may need to undergo major corrective surgery soon after birth. Other individuals may have relatively minor health problems requiring no therapy.

Examination at birth

Initial examination of newborns with DS should pay particular attention to certain physical signs that are more commonly found in DS. Evaluation of the red reflex
Red reflex
The red reflex refers to the reddish-orange reflection from the eye's retina that is observed when using an ophthalmoscope or retinoscope from approximately 30 cm / 1 foot...

 can help identify congenital cataract
Cataract
A cataract is a clouding that develops in the crystalline lens of the eye or in its envelope, varying in degree from slight to complete opacity and obstructing the passage of light...

s. Movement of the eyes should be observed to identify strabismus
Strabismus
Strabismus is a condition in which the eyes are not properly aligned with each other. It typically involves a lack of coordination between the extraocular muscles, which prevents bringing the gaze of each eye to the same point in space and preventing proper binocular vision, which may adversely...

. Constipation should raise concerns for Hirschsprung's disease
Hirschsprung's disease
Hirschsprung's disease , or congenital aganglionic megacolon is a serious medical problem where the enteric nervous system is missing from the end of the bowel. The enteric nervous system is a complex network of neurons and glia that controls most aspects of intestinal function...

 and feeding problems should prompt intense education to ensure adequate input and nutrition.

At birth, an ultrasound of the heart (echocardiogram) should be done immediately in order to identify congenital heart disease (this should be carried out by someone with experience in pediatric cardiology). A complete blood count should be done in order to identify pre-existing leukemia. A hearing test using brainstem auditory evoked responses
Evoked potential
An evoked potential is an electrical potential recorded from the nervous system of a human or other animal following presentation of a stimulus, as distinct from spontaneous potentials as detected by electroencephalography or electromyography .Evoked potential amplitudes tend to be low, ranging...

 (BAERS) testing should be performed and any hearing deficits further characterized. The thyroid function should also be tested. Early Childhood Intervention
Early Childhood Intervention
Early childhood intervention is a support system for children with developmental disabilities or delays and their families.The mission of Early Childhood Intervention is to assure that families who have children ages birth to three, with diagnosed disabilities, developmental delays or substantial...

 should be involved from birth to help coordinate and plan effective strategies for learning and development.

The American Academy of Pediatrics
American Academy of Pediatrics
The American Academy of Pediatrics is the major professional association of pediatricians in the United States. The AAP was founded in 1930 by 35 pediatricians to address pediatric healthcare standards. It currently has 60,000 members in primary care and sub-specialist areas...

, among other health organizations, has issued a series of recommendations for screening
Screening (medicine)
Screening, in medicine, is a strategy used in a population to detect a disease in individuals without signs or symptoms of that disease. Unlike what generally happens in medicine, screening tests are performed on persons without any clinical sign of disease....

 individuals with Down syndrome for particular diseases. These guidelines enable health care providers to identify and prevent important aspects of DS. All other typical newborn, childhood, and adult screening and vaccination programs should also be performed.

Plastic surgery

Plastic surgery
Plastic surgery
Plastic surgery is a medical specialty concerned with the correction or restoration of form and function. Though cosmetic or aesthetic surgery is the best-known kind of plastic surgery, most plastic surgery is not cosmetic: plastic surgery includes many types of reconstructive surgery, hand...

 has sometimes been advocated and performed on children with Down syndrome, based on the assumption that surgery can reduce the facial features associated with Down syndrome, therefore decreasing social stigma, and leading to a better quality of life. Plastic surgery on children with Down syndrome is uncommon, and continues to be controversial. Researchers have found that for facial reconstruction, "...although most patients reported improvements in their child's speech and appearance, independent raters could not readily discern improvement...." For partial glossectomy (tongue reduction), one researcher found that 1 out of 3 patients "achieved oral competence," with 2 out of 3 showing speech improvement. Len Leshin, physician and author of the ds-health website, has stated, "Despite being in use for over twenty years, there is still not a lot of solid evidence in favor of the use of plastic surgery in children with Down syndrome." The U.S. National Down Syndrome Society
National Down Syndrome Society
The National Down Syndrome Society is an American organization which offers support to people and families with Down syndrome, as well as educating the general public about Down syndrome. The organization was founded in 1979...

 has issued a "Position Statement on Cosmetic Surgery for Children with Down Syndrome", which states "The goal of inclusion and acceptance is mutual respect based on who we are as individuals, not how we look."

Cognitive development

The identification of the best methods of teaching each particular child ideally begins soon after birth through early intervention programs. Cognitive development
Cognitive development
Cognitive development is a field of study in neuroscience and psychology focusing on a child's development in terms of information processing, conceptual resources, perceptual skill, language learning, and other aspects of brain development and cognitive psychology compared to an adult's point of...

 in children with Down syndrome is quite variable. It is not currently possible at birth to predict the capabilities of any individual reliably, nor are the number or appearance of physical features predictive of future ability. Since children with Down syndrome have a wide range of abilities, success at school can vary greatly, which underlines the importance of evaluating children individually. The cognitive problems that are found among children with Down syndrome can also be found among other children. Therefore, parents can use general programs that are offered through the schools or other means.

Individuals with Down syndrome differ considerably in their language and communication skills. It is routine to screen for middle ear problems and hearing loss; low gain hearing aids or other amplification devices can be useful for language learning. Early communication intervention fosters linguistic skills. Language assessments can help profile strengths and weaknesses; for example, it is common for receptive language skills to exceed expressive skills. Individualized speech therapy can target specific speech errors, increase speech intelligibility, and in some cases encourage advanced language and literacy. Augmentative and alternative communication
Augmentative and alternative communication
Augmentative and alternative communication is an umbrella term that encompasses the communication methods used to supplement or replace speech or writing for those with impairments in the production or comprehension of spoken or written language...

 (AAC) methods, such as pointing, body language, objects, or graphics are often used to aid communication. Relatively little research has focused on the effectiveness of communications intervention strategies.

In education, mainstreaming
Mainstreaming in education
Mainstreaming in the context of education is a term that refers to the practice of educating students with special needs in regular classes during specific time periods based on their skills. This means regular education classes are combined with special education classes...

 of children with Down syndrome is becoming less controversial in many countries. For example, there is a presumption of mainstream in many parts of the UK. Mainstreaming is the process whereby students of differing abilities are placed in classes with their chronological peers. Children with Down syndrome may not age emotionally/socially and intellectually at the same rates as children without Down syndrome, so over time the intellectual and emotional gap between children with and without Down syndrome may widen. Complex thinking as required in sciences but also in history, the arts, and other subjects can often be beyond the abilities of some, or achieved much later than in other children. Therefore, children with Down syndrome may benefit from mainstreaming provided that some adjustments are made to the curriculum.

Some European countries such as Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 and Denmark
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...

 advise a two-teacher system, whereby the second teacher takes over a group of children with disabilities within the class. A popular alternative is cooperation between special schools and mainstream schools. In cooperation, the core subjects are taught in separate classes, which neither slows down the typical students nor neglects the students with disabilities. Social activities, outings, and many sports and arts activities are performed together, as are all breaks and meals.

Speech delay may require speech therapy
Speech and language pathology
Speech-Language Pathology specializes in communication disorders.The main components of speech production include: phonation, the process of sound production; resonance, opening and closing of the vocal folds; intonation, the variation of pitch; and voice, including aeromechanical components of...

 to improve expressive language.

Childhood and adulthood follow-up

As children with DS grow, their progress should be plotted on a growth chart
Growth chart
A growth chart is used by pediatricians and other health care providers to follow a child's growth over time. Growth charts have been constructed by observing the growth of large numbers of normal children over time...

 in order to detect deviations from expected growth. Special growth charts are available so that children with DS can be compared with other children with DS. Thyroid function testing should be performed at 6 months and 12 months of age as well as yearly thereafter. Evaluation of the ears for infection as well as objective hearing tests should be performed at every visit. Formal evaluation for refractive errors requiring glasses should be performed at least every two years with subjective vision assessments with each visit. After the age of three, an x-ray of the neck should be obtained to screen for atlanto-axial instability. As the child ages, yearly symptom screening for obstructive sleep apnea should be performed.

Alternative treatment

The Institutes for the Achievement of Human Potential
The Institutes for The Achievement of Human Potential
The Institutes for The Achievement of Human Potential is a non-profit organization providing teaching programs and literature which it promotes as improving the health and neurological development of normal children and of children who have sustained a brain injury.Although the institute's programs...

 is a nonprofit organization that treats children who have, as the IAHP terms it, "some form of brain injury," including children with Down syndrome. The approach of "Psychomotor Patterning" is not proven, and is considered alternative medicine
Alternative medicine
Alternative medicine is any healing practice, "that does not fall within the realm of conventional medicine." It is based on historical or cultural traditions, rather than on scientific evidence....

.

Some experimental work with memantine - a NMDA-dampener usually used for Alzheimer’s - is being conducted by Alberto Costa, a physician and neuroscientist at University of Colorado.

Research

Down syndrome is “a developmental condition characterized by trisomy
Trisomy
A trisomy is a type of polysomy in which there are three copies, instead of the normal two, of a particular chromosome. A trisomy is a type of aneuploidy .-Description and causes:...

 of human chromosome 21" (Nelson 619). The extra copy of chromosome-21 leads to an over expression of certain genes
Gênes
Gênes is the name of a département of the First French Empire in present Italy, named after the city of Genoa. It was formed in 1805, when Napoleon Bonaparte occupied the Republic of Genoa. Its capital was Genoa, and it was divided in the arrondissements of Genoa, Bobbio, Novi Ligure, Tortona and...

 located on chromosome-21.

Research by Arron et al. shows that some of the phenotypes associated with Down syndrome can be related to the disregulation of transcription factors (596), and in particular, NFAT
NFAT
Nuclear factor of activated T-cells is a general name applied to a family of transcription factors shown to be important in immune response. One or more members of the NFAT family is expressed in most cells of the immune system...

. NFAT is controlled in part by two proteins, DSCR1 and DYRK1A; these genes are located on chromosome-21 (Epstein 582). In people with Down syndrome, these proteins have 1.5 times greater concentration than normal (Arron et al. 597). The elevated levels of DSCR1 and DYRK1A keep NFAT primarily located in the cytoplasm
Cytoplasm
The cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the cytoplasm...

 rather than in the nucleus, preventing NFATc from activating the transcription
Transcription (genetics)
Transcription is the process of creating a complementary RNA copy of a sequence of DNA. Both RNA and DNA are nucleic acids, which use base pairs of nucleotides as a complementary language that can be converted back and forth from DNA to RNA by the action of the correct enzymes...

 of target genes and thus the production of certain proteins (Epstein 583).

This disregulation was discovered by testing in transgenic mice that had segments of their chromosomes duplicated to simulate a human chromosome-21 trisomy (Arron et al. 597). A test involving grip strength showed that the genetically modified mice had a significantly weaker grip, much like the characteristically poor muscle tone of an individual with Down syndrome (Arron et al. 596). The mice squeezed a probe with a paw and displayed a .2 newton weaker grip (Arron et al. 596). Down syndrome is also characterized by increased socialization. When modified and unmodified mice were observed for social interaction, the modified mice showed as much as 25% more interactions as compared to the unmodified mice (Arron et al. 596).

The genes that may be responsible for the phenotypes associated may be located proximal to 21q22.3. Testing by Olson and others in transgenic mice show the duplicated genes presumed to cause the phenotypes are not enough to cause the exact features. While the mice had sections of multiple genes duplicated to approximate a human chromosome-21 triplication, they only showed slight craniofacial abnormalities (688–90). The transgenic mice were compared to mice that had no gene duplication by measuring distances on various points on their skeletal structure and comparing them to the normal mice (Olson et al. 687). The exact characteristics of Down syndrome were not observed, so more genes involved for Down syndrome phenotypes have to be located elsewhere.

Reeves et al., using 250 clones of chromosome-21 and specific gene markers, were able to map the gene in mutated bacteria. The testing had 99.7% coverage of the gene with 99.9995% accuracy due to multiple redundancies in the mapping techniques. In the study 225 genes were identified (311–13).

The search for major genes that may be involved in Down syndrome symptoms is normally in the region 21q21–21q22.3. However, studies by Reeves et al. show that 41% of the genes on chromosome-21 have no functional purpose, and only 54% of functional genes have a known protein sequence. Functionality of genes was determined by a computer using exon
Exon
An exon is a nucleic acid sequence that is represented in the mature form of an RNA molecule either after portions of a precursor RNA have been removed by cis-splicing or when two or more precursor RNA molecules have been ligated by trans-splicing. The mature RNA molecule can be a messenger RNA...

 prediction analysis (312). Exon sequence was obtained by the same procedures of the chromosome-21 mapping.

Research has led to an understanding that two genes located on chromosome-21, that code for proteins that control gene regulators, DSCR1 and DYRK1A can be responsible for some of the phenotypes associated with Down syndrome. DSCR1 and DYRK1A cannot be blamed outright for the symptoms; there are a lot of genes that have no known purpose. Much more research would be needed to produce any appropriate or ethically acceptable treatment options.

Recent use of transgenic
Genetically modified organism
A genetically modified organism or genetically engineered organism is an organism whose genetic material has been altered using genetic engineering techniques. These techniques, generally known as recombinant DNA technology, use DNA molecules from different sources, which are combined into one...

 mice
Mouse
A mouse is a small mammal belonging to the order of rodents. The best known mouse species is the common house mouse . It is also a popular pet. In some places, certain kinds of field mice are also common. This rodent is eaten by large birds such as hawks and eagles...

 to study specific genes in the Down syndrome critical region has yielded some results. APP
Amyloid beta
Amyloid beta is a peptide of 36–43 amino acids that is processed from the Amyloid precursor protein. While it is most commonly known in association with Alzheimer's disease, it does not exist specifically to cause disease...

 is an Amyloid beta A4 precursor protein. It is suspected to have a major role in cognitive difficulties. Another gene, ETS2 is Avian Erythroblastosis Virus E26 Oncogene Homolog 2. Researchers have "demonstrated that over-expression of ETS2 results in apoptosis
Apoptosis
Apoptosis is the process of programmed cell death that may occur in multicellular organisms. Biochemical events lead to characteristic cell changes and death. These changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation...

. Transgenic mice over-expressing ETS2 developed a smaller thymus and lymphocyte abnormalities, similar to features observed in Down syndrome."

Human chromosome 21 contains five microRNA genes: miR-99a
Mir-10 microRNA precursor family
The miR-10 microRNA precursor is a short non-coding RNA gene involved in gene regulation. It is part of an RNA gene family which contains miR-10, miR-51, miR-57, miR-99 and miR-100. miR-10, miR-99 and miR-100 have now been predicted or experimentally confirmed in a wide range of species...

, let-7c
Let-7 microRNA precursor
The Let-7 microRNA precursor was identified from a study of developmental timing in C. elegans, and was later shown to be part of a much larger class of non-coding RNAs termed microRNAs. miR-98 microRNA precursor from human is a let-7 family member. Let-7 miRNAs have now been predicted or...

, miR-125b-2, miR-155,and miR-802. MiR-155 and miR-802 regulate the expression of the methyl-CpG-binding protein (MeCP2
MECP2
MECP2 is a gene that provides instructions for making its protein product, MECP2, also referred to as MeCP2. MECP2 appears to be essential for the normal function of nerve cells. The protein seems to be particularly important for mature nerve cells, where it is present in high levels...

). It has been suggested that the underexpression of MeCP2, secondary to trisomic overexpression of Human chromosome 21 derived miRNAs, may result in aberrant expression of the transcription factor
Transcription factor
In molecular biology and genetics, a transcription factor is a protein that binds to specific DNA sequences, thereby controlling the flow of genetic information from DNA to mRNA...

s of CREB1
CREB1
CAMP responsive element binding protein 1, also known as CREB-1, is a protein that in humans is encoded by the CREB1 gene. This protein binds the cAMP response element, a DNA nucleotide sequence present in many viral and cellular promoters...

 and MEF2C
MEF2C
Myocyte-specific enhancer factor 2C also known as MADS box transcription enhancer factor 2, polypeptide C is a protein that in humans is encoded by the MEF2C gene. MEF2C is a transcription factor in the Mef2 family.-Genomics:...

 . This in turn may lead to abnormal brain development through anomalous neuronal gene expression during the critical period of synaptic maturation by alterating neurogenesis
Neurogenesis
Neurogenesis is the process by which neurons are generated from neural stem and progenitor cells. Most active during pre-natal development, neurogenesis is responsible for populating the growing brain with neurons. Recently neurogenesis was shown to continue in several small parts of the brain of...

, neuronal differentiation, myelination, and synaptogenesis
Synaptogenesis
Synaptogenesis is the formation of synapses. Although it occurs throughout a healthy person's lifespan, an explosion of synapse formation occurs during early brain development...

.

Society

Advocates for people with Down syndrome point to various factors, such as additional educational support and parental support groups to improve parenting knowledge and skills. There are also strides being made in education, housing, and social settings to create environments that are accessible and supportive to people with Down syndrome. In most developed countries, since the early 20th century many people with Down syndrome were housed in institutions or colonies and excluded from society. However, since the early 1960s parents and their organizations, educators and other professionals have generally advocated a policy of inclusion, bringing people with any form of mental or physical disability into general society as much as possible. Such organizations included the National Association for Down Syndrome, the first known organization advocating for Down syndrome individuals in the United States founded by Kathryn McGee in 1960; MENCAP advocating for all with mental disabilities, which was founded in the UK in 1946 by Judy Fryd; and the National Down Syndrome Congress, the first truly national organization in the U.S. advocating for Down syndrome families, founded in 1973 by Kathryn McGee
Kathryn McGee
Kathryn McGee has been recognized for founding two of the first organizations for the benefit of those with Down Syndrome. She is retired and living in River Forest, Illinois. She worked seeking recognition, rights and opportunities for people with Down Syndrome...

 and others. In many countries, people with Down syndrome are educated in the normal school system; there are increasingly higher-quality opportunities to move from special (segregated) education to regular education settings.

Despite these changes, the additional support needs of people with Down syndrome can still pose a challenge to parents and families. Although living with family is preferable to institutionalization, people with Down syndrome often encounter patronizing attitudes and discrimination
Discrimination
Discrimination is the prejudicial treatment of an individual based on their membership in a certain group or category. It involves the actual behaviors towards groups such as excluding or restricting members of one group from opportunities that are available to another group. The term began to be...

 in the wider community.

The first World Down Syndrome Day
World Down Syndrome Day
World Down Syndrome Day , is on 21st April. On this day, Down syndrome organizations throughout the world organize and participate in events to raise public awareness of Down syndrome....

 was held on 21 March 2006. The day and month were chosen to correspond with 21 and trisomy respectively. It was proclaimed by European Down Syndrome Association during their European congress in Palma de Mallorca (febr. 2005). In the United States, the National Down Syndrome Society observes Down Syndrome Month every October as "a forum for dispelling stereotypes, providing accurate information, and raising awareness of the potential of individuals with Down syndrome." In South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

, Down Syndrome Awareness Day is held every October 20.
Organizations such as Special Olympics Hawaii provide year-round sports training for individuals with intellectual disabilities such as Down syndrome.

Notable individuals

  • Danny Alsabbagh
    Danny Alsabbagh
    Danny Alsabbagh is an Australian actor who played Toby Alsabbagh in the 2007 Australian Broadcasting Corporation TV series Summer Heights High. He later appeared in the music video "Naughty Girl"....

    , Australian actor who played Toby in the Australian mockumentary
    Mockumentary
    A mockumentary , is a type of film or television show in which fictitious events are presented in documentary format. These productions are often used to analyze or comment on current events and issues by using a fictitious setting, or to parody the documentary form itself...

     series Summer Heights High
    Summer Heights High
    Summer Heights High is a Logie Award-winning Australian television mockumentary series written by and starring Chris Lilley. It is a parody of high-school life epitomised by its three protagonists: effeminate and megalomaniacal "Director of Performing Arts" Mr G; self-absorbed, privileged teenager...

  • Chris Burke
    Chris Burke (actor)
    Christopher Joseph "Chris" Burke is an American actor, living with Down syndrome, who has become best known for his character Charles "Corky" Thacher on the television series Life Goes On.- Early Years :...

    , American actor who portrayed "Corky Thatcher" on the television series Life Goes On
    Life Goes On (TV series)
    Life Goes On is a television series that aired on ABC from September 12, 1989 to May 23, 1993. The show centers on the Thacher family living in suburban Chicago: Drew, his wife Elizabeth, and their children Paige, Rebecca, and Charles, who is known as Corky...

    and "Taylor" on Touched By An Angel
    Touched by an Angel
    Touched by an Angel is an American drama series that premiered on CBS on September 21, 1994 and ran for 211 episodes and nine seasons until its conclusion on April 27, 2003. Created by John Masius and produced by Martha Williamson, the series stars Roma Downey, as an angel named Monica, and Della...

    .
  • Edward Barbanell
    Edward Barbanell
    Edward Barbanell is an American actor with Down syndrome, best known for playing the character of "Billy" in the 2005 film The Ringer. He attended Coral Springs High School....

    , played Billy in 2005's The Ringer.
  • Pascal Duquenne
    Pascal Duquenne
    Pascal Duquenne is a Belgian actor. He shared the prize for a male role in 1996 Cannes Film Festival for his performance as Georges in the movie The Eighth Day, with Daniel Auteuil, who played Harry. He currently lives in Brussels...

    , Belgian film actor, co-starred with Daniel Auteuil
    Daniel Auteuil
    Daniel Auteuil is a French film, television and theatre actor.-Early life and education:He was born in Algiers, French Algeria.-Career:...

     in the 1996 film Le Huitième Jour
    Le Huitième Jour
    Le huitième jour is a Belgian 1996 film that tells the story of the friendship that develops between two men who meet by chance...

    (The Eighth Day), both actors won the joint award for Best Actor at the Cannes Film Festival
    Cannes Film Festival
    The Cannes International Film Festival , is an annual film festival held in Cannes, France, which previews new films of all genres including documentaries from around the world. Founded in 1946, it is among the world's most prestigious and publicized film festivals...

    .
  • Andrea Friedman
    Andrea Fay Friedman
    Andrea Fay Friedman is an American film and television actress with Down syndrome.-Early life:Friedman attended West Los Angeles Baptist High School and Santa Monica College. In 1992, she portrayed Amanda, the girlfriend of the character Charles "Corky" Thatcher, on the TV show Life Goes On for...

    : actress who portrayed Corky's girlfriend Amanda in Life Goes On and Ellen in the Family Guy
    Family Guy
    Family Guy is an American animated television series created by Seth MacFarlane for the Fox Broadcasting Company. The series centers on the Griffins, a dysfunctional family consisting of parents Peter and Lois; their children Meg, Chris, and Stewie; and their anthropomorphic pet dog Brian...

    episode "Extra Large Medium
    Extra Large Medium
    "Extra Large Medium" is the twelfth episode of the eighth season of the animated comedy series Family Guy. Directed by John Holmquist and written by Steve Callaghan, the episode originally aired on Fox in the United States on February 14, 2010...

    ".
  • Stephane Ginnsz, actor (Duo
    Duo (film)
    Duo: The True Story of a Gifted Child with Down Syndrome is a 1996 independent film starring Stephane Ginnsz. It is notable for featuring the first lead actor with Down syndrome.-Awards:Duo won both the Martin Scorsese and the Warner Bros...

    )—In 1996 was first actor with Down syndrome in the lead part of a motion picture.
  • Nigel Hunt, British author (The World Of Nigel Hunt; The Diary Of A Mongoloid Youth—this book was published in 1967, when "mongoloid" was still quite commonly used to refer to people with Down syndrome).
  • Tommy Jessop, British actor who played Ben in Coming Down the Mountain
    Coming Down the Mountain
    Coming Down the Mountain is a 2007 British television movie which was shown on BBC One, written by Mark Haddon and directed by Julie Anne Robinson. The television movie was based on a radio play also written by Haddon.-Plot:David and Ben Philips are teenage brothers who live in London. Ben has...

    , opposite Nicholas Hoult
    Nicholas Hoult
    Nicholas Caradoc Hoult is an English actor, best known for playing Marcus Brewer in the 2002 film About a Boy, Tony Stonem in the E4, BAFTA-winning television series Skins, and Beast in the X-Men prequel, X-Men: First Class.-Early life:Hoult was born in Wokingham, Berkshire, the third of four...

  • Rene Moreno, subject of "Up Syndrome
    Up Syndrome
    Up Syndrome is a critically acclaimed, multi-award winning documentary directed by Duane Graves. It was picked up for distribution by CineClix shortly after its world premiere at the 2001 Slamdance Film Festival in Park City, UT, and made available in the USA via Netflix...

    "—a documentary film about life with Down syndrome.
  • Joey Moss
    Joey Moss
    Joseph Neil "Joey" Moss is the locker room attendant for the Edmonton Oilers of the National Hockey League and the Edmonton Eskimos of the Canadian Football League. Born with Down syndrome, Moss caught the eye of Oilers centre Wayne Gretzky in 1985, when Gretzky was dating Moss's sister, Vicki...

    , Edmonton Oilers
    Edmonton Oilers
    The Edmonton Oilers are a professional ice hockey team based in Edmonton, Alberta, Canada. They are members of the Northwest Division in the Western Conference of the National Hockey League ....

     locker room attendant.
  • Pablo Pineda
    Pablo Pineda
    Pablo Pineda is a Spanish actor who received the Silver Shell award at the 2009 San Sebastián International Film Festival for his performance in the film Yo Tambien. In the film he plays the role of a university graduate with Down syndrome, which is quite similar to his real life.Pineda lives in...

    , Spanish actor who starred in the semi-autobiographical film Yo También.
  • Isabella Pujols, adopted daughter of St. Louis Cardinals
    St. Louis Cardinals
    The St. Louis Cardinals are a professional baseball team based in St. Louis, Missouri. They are members of the Central Division in the National League of Major League Baseball. The Cardinals have won eleven World Series championships, the most of any National League team, and second overall only to...

     first baseman Albert Pujols
    Albert Pujols
    José Alberto Pujols Alcántara , better known as Albert Pujols , is a Dominican-American professional baseball player, who is currently a free agent...

     and inspiration for the Pujols Family Foundation.
  • Paula Sage
    Paula Sage
    Paula Sage is a Scottish actress, Special Olympics netball player, and advocate for people with Down's syndrome from Cumbernauld.-Biography:She is an ambassador for Down's Syndrome Scotland and Mencap, and a patron of the Ann Craft Trust....

    , Scottish film actress and Special Olympics
    Special Olympics
    Special Olympics is the world's largest sports organization for children and adults with intellectual disabilities, providing year-round training and competitions to more than 3.1 million athletes in 175 countries....

     netball athlete. Her role in the 2003 film AfterLife
    AfterLife
    AfterLife is a 2003 film drama set in Scotland directed by Alison Peebles and original screen play by Andrea Gibb. An ambitious Scottish journalist forced to choose between his high-flying career or caring for his younger sister who has Down's Syndrome....

    brought her a BAFTA Scotland award for best first time performance and Best Actress in the Bratislava International Film Festival, 2004.
  • John Taylor, American actor who has appeared in such films as The Seventh Sign
    The Seventh Sign
    The Seventh Sign is a 1988 apocalyptic drama film written by Clifford and Ellen Green and directed by Carl Schultz.-Plot:Signs of the apocalypse are appearing, along with a mysterious wanderer. Father Lucci is the Vatican official investigating them...

    , The Ringer, and Jackass 3D
    Jackass 3D
    Jackass 3D is a 2010 American 3D comedy film and the fourth film in the Jackass series. It was released on October 15, 2010 by Paramount Pictures and MTV Films to American theaters and marked the 10th anniversary of the franchise, which started in 2000...

    . He was also the subject of the documentary "Yours to Keep".

General bibliography

  • Hassold, TJ; Patterson, D eds. (1999). Down Syndrome: A Promising Future, Together. New York: Wiley Liss.
  • Pueschel, SM; Sustrova, M eds. (1997). Adolescents with Down Syndrome: Toward a More Fulfilling Life. Baltimore, MD: Brookes Paul H

External links

  • Facts about Down Syndrome from the National Institutes of Health
    National Institutes of Health
    The National Institutes of Health are an agency of the United States Department of Health and Human Services and are the primary agency of the United States government responsible for biomedical and health-related research. Its science and engineering counterpart is the National Science Foundation...

  • Tying Your Own Shoes An animated documentary that provides insight into the lives of four adult artists with Down Syndrome, by National Film Board of Canada
    National Film Board of Canada
    The National Film Board of Canada is Canada's twelve-time Academy Award-winning public film producer and distributor. An agency of the Government of Canada, the NFB produces and distributes documentary, animation, alternative drama and digital media productions...

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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