Ectodermal dysplasia syndromes

**Definition:** Ectodermal dysplasias (EDs) are a heterogeneous group of syndromes characterised by developmental dystrophies of ectodermal structures, such as hypohidrosis, hypotrichosis, onychodysplasia and hypodontia or anodontia. More than 160 clinically and genetically distinct hereditary ectodermal dysplasia syndromes have been catalogued.