Patient Education
What is Ectodermal Dysplasia (ED)?
Ectodermal Dysplasia (ED) is not a single disorder, but a group of closely related conditions of which more than 150 different syndromes have been identified. The Ectodermal Dysplasias (EDs) are genetic disorders affecting the development or function of the teeth, hair, nails, and sweat glands. Depending on the particular syndrome ED can also affect the skin, the lens or retina of the eye, parts of the inner ear, the development of fingers and toes, the nerves, and other parts of the body.
What are symptoms of ED?
- Absence or abnormality of hair growth
- Absence or malformation of some or all teeth
- Inability to perspire, which causes overheating
- Impairment or loss of hearing or vision
- Frequent infections due to immune system deficiencies or, in some cases, the inability of cracked or eroded skin to keep out disease-causing bacteria
- Absence or malformation of some fingers or toes
The inheritance patterns are variable according to the specific type of ED. Patterns include:
- spontaneous mutations
- autosomal dominant
- autosomal recessive
- X-linked dominant
- X-linked recessive
It is important to remember that not all individuals affected by the EDs will have physical features that fit the description of a specific syndrome. There may be a great deal of variation in the physical appearance of the same type of ED from one affected person to the next. It is also conceivable for a person to have a type of ED that has not been described yet. Nonetheless, the EDs share certain features, an understanding of which makes it possible to appreciate the ramifications for most affected individuals and allows everyone involved to respond appropriately to the individual's needs.
What causes ED?
The altered genes may be inherited or normal genes may become defective (mutate) at the time of conception. The chances for parents to have affected children depend on the type of ED that exists in the family. One common type of ED affects males more than females this is the X-linked type of hypohidrotic ED, other types can affect males or females equally and may be inherited in different ways. Prenatal diagnosis is available for some families with X-linked hypohidrotic ectodermal dysplasia, through the use of DNA probes. This is not possible for all families.