Ectodermal dysplasia
Encyclopedia
Ectodermal dysplasia is not a single disorder, but a group of syndromes all deriving from abnormalities of the ectodermal structures. More than 150 different syndrome
s have been identified. Despite some of the syndromes having different genetic causes the symptoms are sometimes very similar. Diagnosis is usually by clinical observation often with the assistance of family medical histories so that it can be determined whether transmission is autosomal dominant or recessive. Worldwide around 7,000 people have been diagnosed with an ectodermal dysplasia condition. Some ED conditions are only present in single family units and derive from very recent mutations. Ectodermal dysplasias can occur in any race but are much more prevalent in caucasians than any other group and especially in fair Caucasians
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Ectodermal dysplasias are described as "heritable conditions in which there are abnormalities of two or more ectoderm
al structures such as the hair
, teeth, nails
, sweat glands, cranial-facial structure, digits and other parts of the body." http://www.ectodermaldysplasia.org
There are several different types with distinct genetic causes:
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Another is famous skateboarder and artist Levi 'Nek Minnit' Hawken, who is well known for his 'Nek Minnit' videos on Youtube.
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...
s have been identified. Despite some of the syndromes having different genetic causes the symptoms are sometimes very similar. Diagnosis is usually by clinical observation often with the assistance of family medical histories so that it can be determined whether transmission is autosomal dominant or recessive. Worldwide around 7,000 people have been diagnosed with an ectodermal dysplasia condition. Some ED conditions are only present in single family units and derive from very recent mutations. Ectodermal dysplasias can occur in any race but are much more prevalent in caucasians than any other group and especially in fair Caucasians
Caucasian race
The term Caucasian race has been used to denote the general physical type of some or all of the populations of Europe, North Africa, the Horn of Africa, Western Asia , Central Asia and South Asia...
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Ectodermal dysplasias are described as "heritable conditions in which there are abnormalities of two or more ectoderm
Ectoderm
The "ectoderm" is one of the three primary germ cell layers in the very early embryo. The other two layers are the mesoderm and endoderm , with the ectoderm as the most exterior layer...
al structures such as the hair
Hair
Hair is a filamentous biomaterial, that grows from follicles found in the dermis. Found exclusively in mammals, hair is one of the defining characteristics of the mammalian class....
, teeth, nails
Nail (anatomy)
A nail is a horn-like envelope covering the dorsal aspect of the terminal phalanges of fingers and toes in humans, most non-human primates, and a few other mammals. Nails are similar to claws, which are found on numerous other animals....
, sweat glands, cranial-facial structure, digits and other parts of the body." http://www.ectodermaldysplasia.org
Genetics
ED can be classified by inheritance (autosomal dominant, autosomal recessive, and X-linked) or by which structures are involved (hair, teeth, nails, and/or sweat glands).There are several different types with distinct genetic causes:
- Hay-Wells syndromeHay-Wells syndromeHay–Wells syndrome is one of at least 150 known types of ectodermal dysplasia.These disorders affect tissues that arise from the ectodermal germ layer, such as skin, hair, and nails.-Genetics:...
, Rapp-Hodgkin syndromeRapp-Hodgkin syndromeRapp–Hodgkin syndrome was formerly thought to be a unique autosomal dominant disorder due to a P63 gene mutation. However, it was recently shown to the same disease as Hay-Wells syndrome.It was first characterized in 1968.-External links:* *...
and EEC syndrome are all associated with TP63.
- Hypohidrotic ectodermal dysplasiaHypohidrotic ectodermal dysplasiaHypohidrotic ectodermal dysplasia is one of about 150 types of ectodermal dysplasia in humans...
can be associated with EDAEDA (gene)Ectodysplasin-A is a protein that in humans is encoded by the EDA gene.-Further reading:...
, EDAREDARTumor necrosis factor receptor superfamily member EDAR is a protein that in humans is encoded by the EDAR gene.It can be associated with Hypohidrotic ectodermal dysplasia.- Further reading :...
, and EDARADDEDARADDEctodysplasin-A receptor-associated adapter protein is a protein that in humans is encoded by the EDARADD gene.-Further reading:...
- Margarita Island ectodermal dysplasia is associated with PVRL1PVRL1Poliovirus receptor-related 1 , also known as PVRL1, is a human gene that encodes a protein of immunoglobulin superfamily also considered a member of the nectins . It is a membrane protein with three extracellular immunoglobulin domains, a single transmembrane helix and a cytoplasmic tail...
- Ectodermal dysplasia with skin fragility is associated with PKP1PKP1Plakophilin-1 is a protein that in humans is encoded by the PKP1 gene.-Interactions:PKP1 has been shown to interact with Desmoplakin.-Further reading:...
- Clouston's hidrotic ectodermal dysplasiaClouston's hidrotic ectodermal dysplasiaClouston's hidrotic ectodermal dysplasia is caused by mutations in a connexin gene, GJB6 or connexin-30, characterized by scalp hair that is...
is associated with GJB6
- Naegeli syndrome/Dermatopathia pigmentosa reticularisDermatopathia pigmentosa reticularisDermatopathia pigmentosa reticularis is a rare, autosomal dominant congenital disorder that is a form of ectodermal dysplasia...
s is associated with KRT14
- Pachyonychia congenitaPachyonychia congenitaPachyonychia congenita, also called Jadassohn-Lewandowski Syndrome or simply pachyonychia, is an autosomal dominant skin disorder.-Symptoms:Common symptoms include:*Excess keratin in nail beds and thickening of the nails...
is caused by multiple keratins
- Focal dermal hypoplasiaFocal dermal hypoplasiaFocal dermal hypoplasia is a form of ectodermal dysplasia.It is also known as Goltz-Gorlin syndrome, after Robert Goltz and Robert Gorlin.It has been associated with PORCN, on the X chromosome.-External links:...
is associated with PORCNPORCNPORCN is a human gene.-Function:The protein encoded by this gene an endoplasmic reticulum transmembrane protein involved in processing of wingless proteins such as WNT7A....
- Ellis–van Creveld syndrome is associated with EVCEVC (gene)EVC is a gene associated with Ellis-van Creveld syndrome. It overlaps with the CRMP1 gene....
- Palmoplantar ectodermal dysplasiaPalmoplantar ectodermal dysplasiaPalmoplantar ectodermal dysplasia is a cutaneous condition.Types include:* Palmoplantar ectodermal dysplasia type 1 or Pachyonychia congenita type I* Palmoplantar ectodermal dysplasia type 3 or Acrokeratoelastoidosis...
refers to several different conditions selectively affecting the hands and feet
Hair
Individuals affected by an ED syndrome frequently have abnormalities of the hair follicles. Scalp and body hair may be thin, sparse, and very light in color, even though beard growth in affected males may be normal. The hair may grow very slowly or sporadically and it may be excessively fragile, curly, or even twisted.Nails
Fingernails and toenails may be thick, abnormally shaped, discolored, ridged, slow-growing, or brittle. The cuticles may be prone to infections.Skin
The skin may be lightly pigmented. Skin sustaining injury may grow back permanently hypo-pigmented. In some cases, red or brown pigmentation may be present. Skin can be prone to rashes or infections and can be thick over the palms and soles. Care must be taken to prevent cracking, bleeding, and infection.Sweat glands
Individuals affected by certain ED syndromes cannot perspire. Their sweat glands may function abnormally or may not have developed at all because of inactive proteins in the sweat glands. Without normal sweat production, the body cannot regulate temperature properly. Therefore, overheating is a common problem, especially during hot weather. Access to cool environments is important.Teeth
In the development of tooth buds frequently result in congenitally absent teeth (in many cases a lack of a permanent set) and/or in the growth of teeth that are peg-shaped or pointed. The enamel may also be defective. Cosmetic dental treatment is almost always necessary and children may need dentures as early as two years of age. Multiple denture replacements are often needed as the child grows, and dental implants may be an option in adolescence, once the jaw is fully grown. Nowadays this option of extracting the teeth and substituting them with dental implants is quite common. In other cases, teeth can be crowned. Orthodontic treatment also may be necessary. Because dental treatment is complex, a multi-disciplinary approach is best.Other features
People with ED often have certain cranial-facial features which can be distinctive, frontal bossing is common, longer or more pronounced chins are frequent, broader noses are also very common. In some types of ED, abnormal development of parts of the eye can result in dryness of the eye, cataracts, and vision defects. Professional eye care can help minimize the effects of ED on vision. Similarly, abnormalities in the development of the ear may cause hearing problems. Respiratory infections can be more common because the normal protective secretions of the mouth and nose are not present. Precautions must be taken to limit infections.Notable cases
One well-known person with ectodermal dysplasia is actor Michael BerrymanMichael Berryman
Michael John Berryman is an American actor. He has appeared in several horror movies and other B movies. Berryman is famous for having a distinctive physical appearance as a result of hypohidrotic ectodermal dysplasia, a rare genetic condition which prevents him from developing hair, sweat glands...
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Another is famous skateboarder and artist Levi 'Nek Minnit' Hawken, who is well known for his 'Nek Minnit' videos on Youtube.