A cleft of the lip and/or palate is a relatively common condition and occurs in about one in 700 children born in the U.S. The rates do vary by ethnicity with higher rates (one in 500) in patients of Asian descent and lower rates (one in 2,000) in patients of African descent. Cleft lip and palate together is the most common combination. It occurs more often in boys than girls and more often on the left side than the right side. Cleft palate alone occurs in about one in 1,500 children born in the U.S. and occurs more often in girls than in boys.
While a cleft palate can be the only medical condition affecting the child, it is common for a cleft of the palate to occur as part of a syndrome. Syndromes often seen with a cleft palate include Stickler syndrome and 22q11 deletion syndrome.
A cleft palate can also be found as part of Pierre Robin sequence. In this condition, the lower jaw is small, and as a result, the tongue is unable to lie well in the floor of the mouth. As a result, the tongue is pushed backward and upward during development. This blocks the two sides of the palate as they move toward one another to form a complete palate. Because the formation of the palate is blocked by the tongue, the two sides do not meet, and a cleft palate results.