[Dominantly inherited lower lip fistulas and facial clefts (Van der Woude syndrome). A study of 52 cases].

Congenital lip pits may occur alone or in combination with oral clefts. They characteristically present as symmetric pits close to the vermilion border of the lower lip, about 0.5 cm off the midline, and are usually connected with heterotopic salivary glands; occasionally, salivation may occur. Congenital lip pits are associated with clefts of the upper lip and/or the palate in about half of the cases. Hypodontia may also be observed. Lip pits with or without clefts are found in a few dominantly inherited syndromes, in most cases involving the autosomal dominant Van der Woude syndrome. 52 carriers of the Van der Woude gene are described. In 8 cases the syndrome occurred as a fresh mutation and the other 44 cases occurred in 5 families. Penetrance was complete and expression very variable. Sex distribution was 1:1. For genetic counselling purposes it can be concluded that all carriers of the Van der Woude gene can be identified. Every symptom (pits, micro-pits, cleft, submucous clefts, uvula bifida) may represent the only manifestation of the gene. The recurrence risks for offspring of gene carriers is 50%, but the risk of severe forms of cleft is much lower.