Abstract: Objective To analyze genetic types and clinical features with anhidrotic ectodermal dysplasia (EDA). Methods The genetic types and clinical manife stations of 35 patients with EDA in five families were analyzed by genealogical investigation and clinical examination. Results ① All patients were males in familiesⅠ,Ⅱ,Ⅳ andⅤ. The females in these families were recessive carriers. Therefore, the genetic types were X.linked EDA. There were 8 males and 6 female s in familyⅢ. The proportion of males to females approximated to 1:1, indica ting autosomal dominant inheritant EDA.② In families with X.linked EDA, TypesⅠ andⅡ were divided according to clinical manifestations of the families. The patients in familiesⅠ and Ⅳ belonged to typeⅠ, with the characteristics of sp ecial appearances, such as defects in the development of hair and sweat glands, hypophrenia and bad sights. Intelligence and physical development were lower than those of general population. However, the patients in familiesⅡ and Ⅴ belonged to typeⅡ. It was characterized by sparse hair, hypohidrosis and inborn teeth less or teeth dysplasia. Intelligence and physical development were the same as general population. In the family with autosomal dominant inheritant EDA, patients manifested hypohidrosis only, and had no other characteristics.③ Histopathol ogy showed defects in the development of hair follicles and sweat glands in pati ents with X.linked EDA, but dysplasia of sweat glands and congenital defect of hair follicles in patients with autosomal dominant inheritant EDA. Conclusion There are variations in hereditary types and clinical manifestations of patients with EDA.

Key words: Ectodermal dysplasia, Hereditary diseases