Ectodermal dysplasia
Ectodermal dysplasia (ED) is a group of genetic syndromes all deriving from abnormalities of the ectodermal structures.[1]: 570 More than 150 different syndromes have been identified.[2]
Ectodermal dysplasia
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.
Ectodermal dysplasias are described as "heritable conditions in which there are abnormalities of two or more ectodermal structures such as the hair, teeth, nails, sweat glands, salivary glands, cranial-facial structure, digits and other parts of the body."
Presentation[edit]
Hair[edit]
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. Kinky hair is also a possibility.
Nails[edit]
Fingernails and toenails may be thick, abnormally shaped, discolored, ridged, slow-growing, or brittle. The cuticles may be prone to infections.
Skin[edit]
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[edit]
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.[3]
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: