An ectodermal dysplasia that is characterized by malformation of ectodermal (skin, hair, teeth and sweat glands) structures including hypotrichosis (sparseness of scalp and body hair), hypohidrosis (reduced ability to sweat), and hypodontia (congenital absence of teeth). [ http://purl.obolibrary.org/obo/ECO_0007636 http://purl.obolibrary.org/obo/ECO_0007637 http://purl.obolibrary.org/obo/ECO_0007646 ]