A cleft lip is an opening in the lip, ranging from a small split to a larger gap that extends to the nose.
A cleft lip is an opening in the lip, ranging from a small split to a larger gap that extends to the nose. Cleft palate is an opening in the roof of the mouth that, like cleft lip, can also vary in size. Someone can have cleft lip and/or cleft palate. Patients with clefts of the palate only (isolated cleft palate) have different inheritance patterns and characteristics from patients with cleft lip and palate or cleft lip alone.
Cleft lip and palate is the most common congenital anomaly of the face and skull, affecting approximately 1 in 600 newborns in the U.S. Of those children born with a cleft:
There are several factors that may increase the risk of having a child with cleft lip and palate. While the inheritance of many genes from either parent and the maternal use of certain medications and substances (maternal smoking, anticonvulsants, alcohol, retinoic acid) are believed to increase the risk of having a child with a cleft, the majority of children born with a cleft of the lip or palate have none of these associated factors.
The way that the inheritance of many genes can affect the risk for having cleft of the lip or palate is difficult to understand. A simplified way to think about it is that there are many genes that slightly increase someone’s risk of having a cleft. The more of these genes a person has, the more likely it is that they will have a cleft. However, it is important to understand that in most cases, a family with a parent or child with a cleft still has a low risk of having more children with clefts of the lip and palate.
The most common scenario is that a family will have a child born with a cleft and no other history of a person with cleft lip and palate in either parent’s family. The risk of this family’s next child having a cleft is about 5% (1 in 20). If a family has one parent with a cleft but no children with a cleft, the risk of their next child having a cleft is about 5% (1 in 20). If a family has no parent with a cleft but two children born with clefts, the risk of their next child having a cleft is about 10% (1 In 10). If a family has one parent and one child with a cleft, the risk of their next child having a cleft approaches 20% (1 in 5). In other words, a family with one parent and one child born with a cleft has an 80% (4 in 5) chance of their next child NOT being born with a cleft. So even when several family members have had a cleft, the risk is higher than the average person, but still relatively low.
There are rare exceptions to this such as Van der Woude syndrome, which demonstrates autosomal dominant inheritance where 50% of a family’s children may be born with a cleft. For this reason, genetic testing should be done when there is a strong family history of clefts
There are two types of cleft lip, unilateral cleft lip and bilateral cleft lip.
Unilateral cleft lip makes up 9 out of 10 of all patients with cleft lip, and is twice as common on the left side as it is on the right. When one side doesn’t reach and connect with the center part of the lip, a unilateral cleft lip occurs. Unilateral cleft lip makes up 9 out of 10 of all patients with cleft lip and is twice as common on the left side as it is on the right.
When both the left and right side fail to meet the center part of the lip during prenatal development, a bilateral cleft lip occurs. Bilateral cleft lip is present in only 1 out of 10 patients with cleft lip.
A baby’s upper lip, nose and roof of the mouth (palate) should form completely 10 weeks into the pregnancy. The two sides of the face fuse together at the philtrum, the normal feature found in the middle portion of the upper lip. The lip forms from three parts – the center part and the left and right side parts.
The left and right parts of the lip grow toward the center as the face is formed early during the pregnancy. Normally the side portions meet and fuse with the center portion. The places where the center and side portions of the lip fuse become the philtral columns. These are the raised ridges extending the vertical length of the lip up to the nose.
The Cupid’s bow is the normal shape of the lip where the red and white portions of the lip meet. The philtral columns meet the lip at the peaks of Cupid’s bow. When these sides do not meet, a cleft lip forms.
Children with cleft lip and palate require specialized care by a cleft team from the time of their birth until they are fully grown. Excellent long-term functional and aesthetic results are the product of a well-coordinated treatment plan through collaboration of all members of the team.