Chromosome 7 is one of the 23 pairs of chromosome

Chromosome

A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...

s in human

Human

Humans are the only living species in the Homo genus...

s. People normally have two copies of this chromosome. Chromosome 7 spans more than 158 million base pair

Base pair

In molecular biology and genetics, the linking between two nitrogenous bases on opposite complementary DNA or certain types of RNA strands that are connected via hydrogen bonds is called a base pair...

s (the building material of DNA

DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

) and represents between 5 and 5.5 percent of the total DNA in cells

Cell (biology)

The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

.

Identifying gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

s on each chromosome is an active area of genetic research. Because researchers use different approaches to predict the number of genes on each chromosome, the estimated number of genes varies. Chromosome 7 is likely to contain between 1,000 and 1,400 genes. It also contains the Homeobox

Homeobox

A homeobox is a DNA sequence found within genes that are involved in the regulation of patterns of anatomical development in animals, fungi and plants.- Discovery :...

 A gene cluster.

Diseases & disorders

The following diseases are some of those related to genes on chromosome 7:

• argininosuccinic aciduria
  Argininosuccinic aciduria
  Argininosuccinic aciduria, also called argininosuccinic acidemia, is an inherited disorder that causes the accumulation of argininosuccinic acid in the blood and urine. Some patients may also have an elevation of ammonia, a toxic chemical, which can affect the nervous system...
  
  
• cerebral cavernous malformation
• Charcot-Marie-Tooth disease
  Charcot-Marie-Tooth disease
  Charcot–Marie–Tooth disease- , known also as Morbus Charcot-Marie-Tooth, Charcot-Marie-Tooth neuropathy, hereditary motor and sensory neuropathy , hereditary sensorimotor neuropathy , or peroneal muscular atrophy, is an inherited disorder of nerves that takes different forms...
  
  
• Charcot-Marie-Tooth disease, type 2
• citrullinemia
  Citrullinemia
  Citrullinemia, also called citrullinuria, is an autosomal recessive urea cycle disorder that causes ammonia and other toxic substances to accumulate in the blood....
  
  
• congenital bilateral absence of vas deferens
• cystic fibrosis
  Cystic fibrosis
  Cystic fibrosis is a recessive genetic disease affecting most critically the lungs, and also the pancreas, liver, and intestine...
  
  
• distal spinal muscular atrophy, type V
• Ehlers-Danlos syndrome
  Ehlers-Danlos syndrome
  Ehlers–Danlos syndrome is a group of inherited connective tissue disorders, caused by a defect in the synthesis of collagen . The collagen in connective tissue helps tissues to resist deformation...
  
  
• Ehlers-Danlos syndrome, arthrochalasia type
• Ehlers-Danlos syndrome, classical type
• hemochromatosis
• hemochromatosis, type 3
• hereditary nonpolyposis colorectal cancer
  Hereditary nonpolyposis colorectal cancer
  Lynch syndrome is an autosomal dominant genetic condition which has a high risk of colon cancer as well as other cancers including endometrium, ovary, stomach, small intestine, hepatobiliary tract, upper urinary tract, brain, and skin...
  
  
• lissencephaly
  Lissencephaly
  Lissencephaly, which literally means smooth brain, is a rare brain formation disorder caused by defective neuronal migration during the 12th to 24th weeks of gestation, resulting in a lack of development of brain folds and grooves . It is a form of cephalic disorder...
  
  
• maple syrup urine disease
  Maple syrup urine disease
  Maple syrup urine disease , also called branched-chain ketoaciduria, is an autosomal recessive metabolic disorder affecting branched-chain amino acids. It is one type of organic acidemia...
  
  
• maturity onset diabetes of the young
  Maturity onset diabetes of the young
  Maturity onset diabetes of the young refers to any of several hereditary forms of diabetes caused by mutations in an autosomal dominant gene disrupting insulin production...
  
   type 2
• mucopolysaccharidosis type VII or Sly syndrome
  Sly syndrome
  Sly syndrome, also called Mucopolysaccharidosis Type VII or MPS, is an autosomal recessive lysosomal storage disease characterized by a deficiency of the enzyme β-glucuronidase, a lysosomal enzyme. Sly syndrome belongs to a group of disorders known as mucopolysaccharidoses, which are lysosomal...
  
  
• myelodysplastic syndrome
  Myelodysplastic syndrome
  The myelodysplastic syndromes are a diverse collection of hematological medical conditions that involve ineffective production of the myeloid class of blood cells....
  
  
• nonsyndromic deafness
  Nonsyndromic deafness
  Nonsyndromic deafness is hearing loss that is not associated with other signs and symptoms. In contrast, syndromic deafness involves hearing loss that occurs with abnormalities in other parts of the body....
  
  
• nonsyndromic deafness, autosomal dominant
• nonsyndromic deafness, autosomal recessive
• osteogenesis imperfecta
  Osteogenesis imperfecta
  Osteogenesis imperfecta is a genetic bone disorder. People with OI are born with defective connective tissue, or without the ability to make it, usually because of a deficiency of Type-I collagen...
  
  
• osteogenesis imperfecta, type I
• osteogenesis imperfecta, type II
• osteogenesis imperfecta, type III
• osteogenesis imperfecta, type IV
• p47-phox-deficient chronic granulomatous disease
• Pendred syndrome
  Pendred syndrome
  Pendred syndrome or Pendred disease is a genetic disorder leading to congenital bilateral sensorineural hearing loss and goitre with occasional hypothyroidism . There is no specific treatment, other than supportive measures for the hearing loss and thyroid hormone supplementation in case of...
  
  
• Romano-Ward syndrome
  Romano-Ward syndrome
  Romano-Ward syndrome, is the major variant of long QT syndrome. It is a condition that causes a disruption of the heart's normal rhythm. This disorder is a form of long QT syndrome, which is a heart condition that causes the cardiac muscle to take longer than usual to recharge between beats...
  
  
• Shwachman-Diamond syndrome
• Schizophrenia
  Schizophrenia
  Schizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...
  
  
• Tritanopia or tritanomaly color blindness
  Color blindness
  Color blindness or color vision deficiency is the inability or decreased ability to see color, or perceive color differences, under lighting conditions when color vision is not normally impaired...
  
  
• Williams syndrome
  Williams syndrome
  Williams syndrome is a rare neurodevelopmental disorder characterized by a distinctive, "elfin" facial appearance, along with a low nasal bridge; an unusually cheerful demeanor and ease with strangers; developmental delay coupled with strong language skills; and cardiovascular problems, such as...
  
  

Chromosomal disorders

The following conditions are caused by changes in the structure or number of copies of chromosome 7:

• Williams syndrome
  Williams syndrome
  Williams syndrome is a rare neurodevelopmental disorder characterized by a distinctive, "elfin" facial appearance, along with a low nasal bridge; an unusually cheerful demeanor and ease with strangers; developmental delay coupled with strong language skills; and cardiovascular problems, such as...
  
   is caused by the deletion of genetic material from a portion of the long (q) arm of chromosome 7. The deleted region, which is located at position 11.23 (written as 7q11.23), is designated as the Williams syndrome critical region. This region includes more than 20 genes, and researchers believe that the characteristic features of Williams syndrome are probably related to the loss of multiple genes in this region.

While a few of the specific genes related to Williams syndrome have been identified, the relationship between most of the genes in the deleted region and the signs and symptoms of Williams syndrome is unknown.

• Other changes in the number or structure of chromosome 7 can cause delayed growth and development, mental disorder, characteristic facial features, skeletal abnormalities, delayed speech, and other medical problems. These changes include an extra copy of part of chromosome 7 in each cell (partial 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:...
  
   7) or a missing segment of the chromosome in each cell (partial monosomy
  Monosomy
  Monosomy is a form of aneuploidy with the presence of only one chromosome from a pair. Partial monosomy occurs when only a portion of the chromosome has one copy, while the rest has two copies.-Human monosomy:...
  
   7). In some cases, several DNA building blocks (nucleotides) are deleted or duplicated in part of chromosome 7. A circular structure called ring chromosome
  Ring chromosome
  A ring chromosome is a chromosome whose arms have fused together to form a ring. A ring chromosome is denoted by the symbol r. Ring chromosomes may form in cells following genetic damage by mutagens like radiation, they may also arise spontaneously during development.-Formation:Normally, the ends...
  
  7 is also possible. A ring chromosome occurs when both ends of a broken chromosome are reunited.