A cleft lip is a failure of the lip segments to fuse in the midline. It can affect one side (unilateral cleft lip) or both side (bilateral cleft lip). The severity of the cleft could range from a small notch in the lip to a complete separation of not only the lip but also the gum line and the floor of the nose. A cleft nasal deformity is associated with the cleft lip, and its severity correlates with the severity of the cleft lip.
On the other hand, a cleft palate is an opening in the roof of the mouth, which occurs when the two palatal “shelves” do not fuse together in the midline before birth. Cleft palate severity can vary, ranging from involving the soft palate, the soft and the hard palate, or both with the involvement of the gums.
Cleft lip with or without cleft palate is the most common facial birth defect in the world, with an incidence ranging from 0.2 to 2.3 per 1000 births
The causes of cleft lip and palate are still not well understood. The majority of cases have no known causes. Genetic factors as well as environmental factors such as drugs, infections, maternal illness, maternal alcohol use and, possibly, deficiency of B vitamin folic acid have been cited as possible causes. There are known cases of family history of cleft lip and palate.
A genetic predisposition for clefting has been well established. Although the genetics of orofacial clefting are only partially understood, such information is of great importance in counseling families of affected children. The overall incidence of clefting is higher in whites (1 in 700) and lower in African Americans (1 in 1300). The incidence of isolated cleft palate in whites is 0.5 in 1000. The inci- dence of a cleft lip (with or without an associated cleft of the palate) is higher in males, while the incidence of an isolated cleft palate is higher in females. For unclefted parents with one child with a cleft lip/palate, the risk of having a second child with a cleft is approximately 4%. This risk increases to 9% when there are two affected children. If one parent and one sibling have a cleft, the risk is 17%. As the degree of familial relationship increases, the recurrence risk decreases; first-, second-, and third-degree relatives have 4%, 0.7%, and 0.3% risk, respectively. Further, recurrence risk increases with the severity of the cleft.
Treatment of patients with cleft lip and palate requires not only surgical procedures done at various stages but also requires care paid to any related speech, hearing, middle ear or dental disorders.
The cleft lip is usually repaired at 3 to 4 months of age while the cleft palate is usually repaired between 9 and 12 months of age. Ideally, it is done before the first year of age for speech purposes. Both surgeries require an overnight stay in the hospital.