Definition

The ectodermal dysplasias are a group of hereditary conditions characterized by abnormal hair, teeth, fingernails and toenails, and sweat glands.

Description

All ectodermal dysplasias have a genetic etiology and involve abnormal development and growth of ectodermally derived tissues. The ectoderm is the outermost layer of the developing embryo, which gives rise to the hair, teeth, nails, and skin. More than 100 different ectodermal dysplasia conditions have been described in the medical literature. The most common of these is hypohidrotic ectodermal dysplasia, which may account for up to 80% of all ectodermal dysplasias.

Other ectodermal dysplasia conditions include ectrodactyly-ectodermal dysplasia-clefting (EEC) syndrome, hidrotic ectodermal dysplasia (Clouston syndrome),...