Genetic counselling and genetics of cleft lip and cleft palate.

Modern neonatal care and advanced plastic surgical correction have led to the survival of most newborns with oral clefts. These children are likely to reproduce. A slight increase in the incidence of oral clefts may be expected in the future. The genetics of cleft lip and cleft palate is reviewed. The inheritance is usually multifactorial. With normal parents the risk of having a first affected child with cleft lip is about one per thousand, the risk of having a second affected child 4 per cent and the risk of having a third affected child 10 per cent. If a parent has already a cleft lip, the risk of having a first affected child now is 4 per cent, while the risk of having a second affected child is 10 per cent. The methodology of genetic counseling is given.