Family with "pure" hair-nail ectodermal dysplasia.

"Pure" ectodermal dysplasias are developmental disorders affecting only tissues of ectodermal origin. Two different pure ectodermal dysplasias involving only hair and nails have been described to date. Here we describe congenital nail dystrophy and hypotrichosis associated with folliculitis decalvans in a family suggesting autosomal-dominant transmission. This report documents peculiar clinical and ultrastructural hair findings that fit poorly into previously described conditions. Thus the reported patients could represent a new type of pure ectodermal dysplasia.