Cephalometric evidence for a dominantly inherited predisposition to cleft lip-cleft palate in a single large kindred.

Several studies have demonstrated an association between facial shape in parents and the presence of oral clefts in their offspring. However, these observations have been of little practical value because it has been assumed that facial shape was just one predisposing component among many in a multifactorial model of inheritance. Cephalometric analysis of a large family with 5 generations of affected individuals suggests that facial shape can be used to identify presumed carriers of a major gene associated with an increased risk for oral clefts. Discriminant function analysis indicates that such at risk individuals can be recognized effectively through a combination of increased midfacial and nasal cavity widths, reduced facial height, and a flat facial profile. The ability to identify minimally affected gene carriers within families would provide critical information needed in the search for molecular markers that segregate with the genetic risk for clefting.