Ectodermal Dysplasia 1, Hypohidrotic, X-Linked (XHED) a congenital disorder wherein affected individuals have abnormal development of two or more ectodermal structures. Most patients have a reduced ability to sweat, sparse scalp and body hair, absent teeth and facial dysmorphism. The dysmorphic facial features may include forehead bumps, rings under the eyes, everted nose, and/or prominent lips.
Mutations in the EDA gene, located on the long arm of chromosome X have been shown to be causal for the condition.