Genetic studies of a cleft palate clinic population

The genetic program at the Lancaster Cleft Palate Clinic is briefly described. The aim of the study is to obtain quantitative estimates of various components which contribute to genetic heterogeneity. Of 260 families interviewed, 26.1% of cleft lip, 42.5% of cleft lip and palate and 30.0% of isolated cleft palate propositi had one or more affected relatives. That isolated cleft palate is etiologically distinct from cleft lip with or without cleft palate is once again demonstrated. Eight of the cleft palate propositi are from mixed pedigrees with Van der Woude syndrome. While a majority of the familial cleft cases are compatible with the multifactorial hypothesis, five pedigrees of cleft lip and cleft palate propositi and one of a cleft palate propositus are in apparent agreement with the hypothesis of single autosomal dominant gene in each pedigree. No case of sex-linked inheritance was found.