Ectodermal Dysplasia

**Definition:** A group of hereditary disorders involving tissues and structures derived from the embryonic ectoderm. They are characterized by the presence of abnormalities at birth and involvement of both the epidermis and skin appendages. They are generally nonprogressive and diffuse. Various forms exist, including anhidrotic and hidrotic dysplasias, FOCAL DERMAL HYPOPLASIA, and aplasia cutis congenita.

**Tree numbers:** - C16.131.077.350 - C16.131.831.350 - C16.320.850.250 - C17.800.804.350 - C17.800.827.250

**Synonyms:** - Congenital Ectodermal Defect - Defect, Congenital Ectodermal - Ectodermal Defect, Congenital