Heterogeneity of facial clefts


A cleft is an opening between segments of the lip or palate that should have closed during the first weeks of fetal development (5th to 9th week of pregnancy).

A cleft lip may be on one side or affect both sides with various degrees of severity. If present only on one side, it is “unilateral”; on boith sides it is “bilateral” (Fig.1 to 2). Since the lip and palate develop separately, the child may have an isolated cleft of the lip or palate or a combined cleft of the lip and palate.

Fig.1  Partial unilateral left cleft of the lip



Fig.2  Complete cleft of the lip and palate


Fig.3  Bilateral cleft of the lip and palate (with a normal premaxilla)


Fig.4 Bilateral cleft of the lip and palate (with a hypoplasic premaxilla)


Everyone is wondering about the real causes of congenital malformations and facial clefts in particular. Multiple causes certainly come into play. What is certain is that scientific research is very active in this area, also at the level of prevention.

The majority of facial clefts appear to be due to a combination of hereditary (genes) and environmental factors. Parents may wonder if they have any responsibility for the appearance of this malformation. We know that it is not caused by the parents’ behaviours, acts or feelings. They should not feel guilty in any way.