EDA Gene

Hypohidrotic ectodermal dysplasia is one of more than 100 types of ectodermal dysplasia. Starting before birth, these disorders result in the abnormal development of ectodermal tissues, particularly the skin, hair, nails, teeth, and sweat glands.

Most people with hypohidrotic ectodermal dysplasia have a reduced ability to sweat (hypohidrosis) because they have fewer sweat glands than normal or their sweat glands do not function properly. Sweating is a major way that the body controls its temperature; as sweat evaporates from the skin, it cools the body. Reduced sweating can lead to a dangerously high body temperature (hyperthermia), particularly in hot weather. In some cases, hyperthermia can cause life-threatening health problems.

Affected individuals tend to have sparse scalp and body hair (hypotrichosis). The hair is often light-colored, brittle, and slow-growing. Hypohidrotic ectodermal dysplasia is also characterized by several missing teeth (hypodontia) or teeth that are malformed. The teeth that are present erupt from the gums later than usual and are frequently small and pointed.

Some people with hypohidrotic ectodermal dysplasia have distinctive facial features, including a prominent forehead, thick lips, and a flattened bridge of the nose. Additional features of this condition can include thin, wrinkled, and dark-colored skin around the eyes; chronic skin problems such as eczema; and a bad-smelling discharge from the nostrils (ozena).

Intellectual ability and growth are typically normal in people with hypohidrotic ectodermal dysplasia.