Reports from the MHC data base
There are 186 (July 2013) different types of ectodermal dysplasia (ED), of which hypohidrotic ectodermal dysplasia (HED) is the most common. Of these, the X-linked variety (Christ-Siemens-Touraine syndrome) is the most common, and makes up about 80-90 percent of all ED cases.
1–7 boys:100,000 born (X-linked HED)
HED is caused by mutations in EDA (X-linked HED), EDAR, EDARADD and WNT10A.
The ED diagnosis is made when the development of two out of the four ectodermal structures hair, nails, teeth and sweat glands is abnormal. The lack or reduced function of sweat glands make the natural regulation of body temperature more difficult. The skin is often dry, and the hair is often thin and light in colour, and may be of abnormal structure. Nails can be thin and brittle. Other possible symptoms are dry mucous membranes, dry eyes, and thick, sticky earwax. Low body weight (small amounts of subcutaneous fat) in relation to height is common. Girls/women with X-linked HED have less severe symptoms.
A characteristic appearance is associated with the diagnosis. Tooth buds for primary teeth and permanent teeth are completely or partly lacking. The lack of tooth buds results in reduced jawbone growth in the areas where genes are lacking. Milk teeth appear later than normal. The teeth may be of abnormal shape. If many teeth are missing in the upper jaw, the palate is often flat, and the occlusal height low. Dry mouth is common if salivary glands have reduced function or are lacking completely. Dry mucous membranes in the mouth and throat and the lack of teeth can make chewing and swallowing difficult, and can affect speech somewhat. Vomiting and gastrointestinal problems are common in smaller children.
- In connection with narcosis, the reduced heat regulation and fragile mucous membranes in the nose, mouth and throat should be taken into account.
- Children suffering from ED should be referred to specialist dental care for follow-up and treatment early on. The treatment plan often requires collaboration between specialists in paediatric dentistry, orthodontics, prosthodontics and oral surgery.
- Teeth should be x-rayed before the child reaches school age.
- It may be appropriate to try out some form of tooth replacement or to rebuild the teeth as early as at the age of three or four.
- The production of saliva should be investigated as early as possible. In cases of dry mouth, dentistry often requires increased levels of care.
- Any speech difficulties are investigated and treated by a speech therapist.
- The rare disease database of the Swedish National Board of Health and Welfare.
- The MHC database - The Mun-H-Center database on oral health and orofacial function in rare diseases.
- The Documentation from the Ågrenska national competence centre for rare diseases.
- Bergendal B. Orodental manifestations in ectodermal dysplasia-a review. Am J Med Genet A. 2014;164A:2465-2471.