Chromosomal and Genetic Conditions

Cleft Lip and Cleft Palate

What Is Cleft Lip and Palate?

Cleft lip and cleft palate are incomplete formations of the upper lip and palate (roof of the mouth) leaving a cleft (gap) in the affected area. Clefts occur when parts of the lip or roof of the mouth don't fuse together during pregnancy.

Cleft lip affects how the lip works and distorts nearby structures like the nose. Cleft lip can occur alone or with cleft palate.

Cleft lip can be unilateral (on one side of the lip) or bilateral (on both sides). Unilateral cleft lip is the mildest cleft form. This form does not usually affect speech or the development of teeth.

In cleft palate, there is an opening in the roof of the mouth. A cleft palate affects speech because the muscles at the back of the palate, which are needed for normal speech, are not formed properly.

A submucous cleft palate is a cleft that is covered by the mucous membrane lining the roof of the mouth. This makes the cleft hard to see when looking in the mouth. But it can affect speech in the same way as a complete cleft palate.

Cleft Lip and Cleft Palate in Children

(Left) Complete unilateral cleft lip and palate (Right) After repair

(Left) Complete unilateral cleft lip and palate.
(Right) Cleft lip and nose repair is done; child is now having cleft palate closure surgery.

Cleft lip and palate are congenital defects, or birth defects, that occur very early in pregnancy between the fourth and eighth week.

Cleft lip and palate are the most common malformations of the head and neck region. Cleft lip and palate occur in all infants but are more common in some races.

In Caucasians, cleft lip with or without cleft palate occurs in around one in 1,000 live births. The rate is twice as common in Asians, and about half as common in African Americans. Around one baby in every 2,000 births has a cleft palate, but no cleft lip.

Most bilateral cleft lips (86%) and unilateral cleft lips (68%) occur with a cleft palate.

Unilateral clefts are nine times as common as bilateral clefts, and occur twice as often on the left side than the right.

Males are more likely to get cleft lip and palate, and females are more likely to get cleft palate alone.

Most cleft lips and palates (60%) are not linked with anything that occurs during or after pregnancy. A few of the exceptions are:

  • Exposure to the drug phenytoin (Dilantin) during pregnancy is linked with a tenfold increase in the rate of cleft lip.
  • Smoking while pregnant doubles the rate of cleft lip.
  • Alcohol, anticonvulsants and retinoic acid (vitamin A) are linked with other birth malformations that include cleft lip and palate.

Genetic abnormalities can result in conditions or syndromes that include cleft lip and palate. A syndrome is a disease or disorder that has more than one identifying feature or symptom.

While cleft lip and palate have a genetic component, a single gene has not been identified.

  • More than 40% of cleft palates are part of malformation syndromes.
  • The most common syndrome associated with cleft lip and palate together is van der Woude syndrome.
  • The most common syndrome linked with cleft palate is velocardiofacial syndrome.

Parents are at greater risk of having a child with clefting if any of these is true:

  • One of the parents has clefting.
  • The parents have already had one or more children with clefting.
  • There are a parent and a child in the family with clefting.
(Left) Complete bilateral cleft lip with twisting of the skin (Right) Incomplete bilateral cleft lip and palate

(Left) Complete bilateral cleft lip with twisting of the skin under the nose and no skin between the nostrils.
(Right) Although this baby was also born with a bilateral cleft lip, these are both incomplete.

The risk level also depends on whether the affected people have cleft lip and palate or only cleft palate. Your doctor can talk with you about the risk level for your family, based on your family history.