Ectodermal dysplasia or Christ-Siemmens syndrome is a congenital defect affecting the development of the ectoderm and mesoderm, and is characterized by a marked decrease or complete absence of sweat, sebaceous and seromucous glands, hypohidrosis, hypotrichosis and hypodontia (oligodontia or anodontia).  The facial appearance of these individuals is characteristic: prominent forehead, fine, scanty and high eyebrows, depressed bridge of the nose (saddle mount), protuberant lips and fine, dry and rough scalp hair.  Those affected suffer from febrile episodes with no apparent cause or after some moderate effort.  Orally, both dentitions may be affected and the mucosa is thin and dry with the expected functional alterations, especially xerostomia and dysphagia. Ectodermal dysplasia is a familial disease which is transmitted in an X-linked, recessive fashion thus having a marked predilection for males. (see photos)