hypohidrotic ectodermal dysplasia (MONDO_0016535, a Monarch Disease Ontology id) is a genetic disorder of ectoderm development characterized by malformation of ectodermal structures such as skin, hair, teeth and sweat glands. It comprises three clinically almost indistinguishable subtypes with impaired sweating as the key symptom: Christ-Siemens-Touraine (CST) syndrome (X-linked), autosomal recessive (AR), and autosomal dominant (AD) HED, as well as a fourth rare subtype with immunodeficiency as the key symptom (HED with immunodeficiency). Also known as: HED, anhidrotic ectodermal dysplasia, anhidrotic ectodermal dysplasia 1, anhidrotic ectodermal dysplasia 3, ectodermal dysplasia 1, Anhydrotic, hypohidrotic X-linked ectodermal dysplasia.