Orofaciodigital syndrome type I (OFD1) is a developmental condition that belongs to a heterogeneous group of Oral-Facial-Digital syndromes. OFD1 is a congenital X-linked dominant disorder characterized by anomalies of the oral cavity, face and digits sometimes associated to cerebral malformations and polycystic kidney disease. Clinically, OFD1 is seen only in females since it is lethal in males. Lesions of the mouth include median pseudoclefting of the upper lip, clefts of the palate and tongue, and dental anomalies (missing or supernumerary teeth, enamel hypoplasia, and teeth malpositions). Dysmorphic features affecting the head include hypertelorism, frontal bossing, micrognathia, facial asymmetry and broadened nasal ridge. Digital anomalies include brachydactyly, syndactyly, clinodactyly, camptodactyly, polydactyly, and hypoplastic thumbs. Less frequently expressed phenotypic anomalies include skin milia, alopecia, deafness and trembling. Some studies have shown that the central nervous system is involved in 50 % of the cases.
Sometimes the diagnosis of OFDI can be difficult because there is an overlap with other types of oral-facial-digital syndromes. However, the X-linked dominant pattern of inheritance and the polycystic kidney disease are typical of OFD1 and differentiate it from the other types of OFD syndromes.
OFD1 syndrome is caused by heterozygous mutation in the OFD1 gene.