Cleft Lip/Cleft Palate: Overview

What is a cleft lip or cleft palate?

A cleft lip is an opening in the lip. A cleft palate is an opening in the roof of the mouth.

A cleft is a common birth defect, something that happens in the early weeks of pregnancy. Since the lip and palate develop separately, it is possible to have a cleft in the lip, gum or palate, or any combination of the three.

A cleft can be unilateral (one side) or bilateral (both sides). A cleft lip can be small a split and not go all the way to the nose (incomplete) or it may go up through the nose (complete). A cleft palate can be a simple notch in the lip, gum or in the back of the palate, or be more extensive and have an opening completely through the lip, gum and palate.

What causes a cleft lip or cleft palate?

The exact cause of clefting is unknown in most cases. For most cleft conditions, no single factor can be identified as the cause. It is important to know the difference between isolated clefts in which the patient has no other related health problems and clefts associated with other issues or syndromes (set of physical, developmental and sometimes behavioral traits that occur together). Family history of clefting can play a role in having a child with a cleft.

  • The causes of cleft lip are numerous, but the majority of cases (approximately 70%) are isolated birth defects caused by the combination of several genetic and environmental factors, most of which have yet to be identified. The remaining 30% occur as part of a genetic syndrome in which there are other associated anomalies, such as birth defects and/or developmental problems.
  • Cleft palate is less common. Cleft palate occurs in 1 in every 2,000 children. The causes of cleft palate are also numerous.  Approximately 40 to 45% of cleft palates occur are caused by the combination of several genetic and environmental factors, most of which have yet to be identified. The remaining 55 to 60% occur as part of a genetic syndrome in which there are other associated anomalies.  

Who gets a cleft lip or cleft palate?

Clefts can occur among all races and in both males and females.  Interestingly, cleft lip and palate occurs about twice as often in boys as girls, while cleft palate alone is slightly more common in girls. In the United States, clefting occurs in about 1 in every 600 births and is one of the most common birth defects.

The incidence of cleft lip/palate is more common in certain ethnic backgrounds, including Asian, Latino and Native American ethnicities.

Helpful resources

More information about Cleft Lip and Palates is available from the following resources: