Van Der Woude syndrome: variable penetrance of a novel mutation (p.Arg 84Gly) of the IRF6 gene in a Turkish family

Van der Woude syndrome (VWS) is an autosomal dominant disorder characterized by clefts of the lip and/or palate (CL+/-P), lip pits, bifid uvula and hypodontia. Mutations of the interferon regulatory factor 6 gene (IRF6) have been recently described in patients with VWS. The entire 9 exons of the IRF6 gene in two brothers of Turkish origin clinically diagnosed with Van der Woude syndrome and four healthy family members were screened for mutations using a newly established denaturing gradient gel electrophoresis (DGGE) method. A novel heterozygous mutation in exon 2 (DNA binding region) of the IRF6 gene, p.Arg84Gly, was found in both brothers with VWS and in their clinically asymptomatic mother. Our results suggest a dominant negative effect of the p.Arg84Gly mutation in the VWS of both patients. Non-penetrance of this mutation is suggested in the mother of the patients.