Cleft lip and/or cleft palate is one of the most common birth defects in the U.S., affecting approximately one in 700 babies. Cleft lip and palate may occur as part of an underlying syndrome or be an isolated birth defect. A cleft lip is the result of the lip not “fusing” together during the first few months of fetal development. This often includes the separation of the upper gum line. A cleft palate, which also occurs during the first few months of fetal development, is a separation in the roof of the mouth caused by the sides of the palate not completely fusing one another.
The severity of cleft lip and cleft palate can vary. A baby can be born with just a cleft lip, just a cleft palate, or both a cleft lip and palate. The clefts are classified as unilateral or bilateral. A unilateral cleft lip or palate affects just one side of the mouth. A bilateral cleft lip or palate affects both sides of the mouth.
Determining Factors of Cleft Lip and Palate
Any one of a variety of factors can come into play to determine if a baby is born with a cleft lip or cleft palate. In most instances, there is no single explanation, but a combination of many factors acting together that results in a cleft lip or palate. However, there are cases which are due to a more comprehensive genetic syndrome that often includes other birth defects. The geneticist evaluates every new patient to determine if the cleft is isolated or part of an underlying syndrome. Isolated cleft lip with or without cleft palate and isolated cleft palate or due to multifactorial causation. Multifactorial causation involves a variety of both genetic and non-genetic factors. This is not due to a single gene abnormality but rather many genes working together along with other factors. We do not know all of the other factors but certainly prenatal exposure to alcohol, cigarettes, high temperatures, and other medications and drugs increases the risk. If a genetic syndrome, such as 22q deletion syndrome is identified, the infant may a have several other physical disorders that will occur as well
Ethnicity and Gender
Although cleft lip with or without cleft palate can occur in any race, there is a higher incidence in people of Asian, Native American or Hispanic decent. There is a lower incidence in African-American individuals.