A genetically and phenotypically heterogenous group of congenital disorders characterized by malformations of the mouth, face, and digits. Typical non-neuroanatomic manifestations include hypertrophic frenula, lingual hamartomas, cleft palate or lip, ocular hypertelorism, brachydactyly, polydactyly, and syndactyly. Associated malformations of the central nervous system are frequently present and psychomotor retardation is common. Porencephaly, hydrocephaly, ependymal cysts, hypothalamic hamartoma, heterotopic neuroglial rests, agenesis of the corpus callosum, cerebellar dysgenesis, and chorioretinal coloboma have been observed in patients with this condition. At least two genetic subtypes distinguished by X-linked dominant and autosomal recessive inheritance have been described, but significant phenotypic overlap exists between the two forms. Prognosis is highly variable and depends on the extent and severity of malformations. Patients with normal intelligence have been reported.