a group of hereditary ectodermal disorders in which the enamel is defective in structure or deficient in quantity. Three major groups are recognized: hypoplastic types, with defective enamel matrix deposition but normal mineralization; hypomineralization types, with normal matrix but defective mineralization; and hypomaturation type, in which the enamel crystallites remain immature. The several types may be inherited as autosomal dominant [MIM*104500, 104510, 104550], recessive [MIM*205650, 204690, 204700] or X-linked [MIM*301100, 301200]. Syn: enamel dysplasia, enamelogenesis imperfecta.