What Causes Cleft Lip?

Cleft lip and palate are treatable birth defects that affect the upper lip and the roof of the mouth. It happens when the tissue that forms in the roof of the mouth and upper lip don’t completely fuse together before birth.

The defects range from a small notch in the lip to a groove that runs into the roof of the mouth and nose, which can lead to problems with speech, ear infections and eating. Surgery is often required to close the lip and palate.

Approximately one in 600 children is born with cleft lip or palate in the United States.

Causes

There are several causes of cleft lip and palate. Problems with genes passed down from one or both parents, viruses, medication use and other toxins can all cause these birth defects.

There appears to be a greater chance of clefting in a newborn if a sibling, parent, or relative has had the problem.

Novel Genes Associated with Cleft Risk

One of the largest family-based, genome-wide studies to date led by a consortium of scientists supported by the National Institutes of Health, identified two genes, that may be associated with cleft lip and/or cleft palate.

With the consent of more than 1,900 affected families from eight countries, the authors were able to detect variations close to genes called MAFB and ABCA4. The variations suggest that altered forms of these genes may be related to clefts. IRF6 gene on chromosome 1 and a region on chromosome 8 were previously identified in other studies.

“The findings pulls together past work, while identifying new potentially casual genes that help to move the science forward,” said Terri H. Beaty, PhD, lead author on the study and professor of Epidemiology at Johns Hopkins Bloomberg School of Public Health.

New Test for Isolated Cleft Lip

Last year, the National Institute of Dental and Craniofacial Research (NIDCR) reported a new test for Isolated Cleft Lip and Palate in which researchers report they can predict whether some parents are more likely than others to have a second child with “isolated” form of cleft lip and palate. The findings were published in the New England Journal of Medicine.

The latest gene test applies to about 12 percent of isolated cleft lip and palate, or babies born with clefts only, not other birth defects.

Environmental Factors

The Centers for Disease Control & Prevention (CDC) reported new factors that may increase the risk of clefts:

Diabetes – women diagnosed with diabetes prior to pregnancy have been shown to have an increased risk of having a child with a cleft lip or palate.

Smoking – women that smoke during pregnancy are more likely to have a baby with an oral cleft compared to those that do not smoke.

Cleft lip and cleft palate may also occur as a result of exposure to viruses or chemicals.

The CDC is currently working on one of the largest studies in the U.S. – the National Birth Defects Prevention Study (NBDPS) – to understand the causes and risk factors for birth defects, including clefts.

Medication Use

Another potential cause of cleft lip and palate is related to medication a mother may have taken during her pregnancy. In fact, in March, the FDA warned about an increased risk of oral clefts in infants exposed to Topamax or generic rivals, during the first trimester of pregnancy. Topamax is an anti-seizure medication also approved for migraine treatment which was newly labeled in Category D.

Acne medications containing Accutane also pose a risk to baby when taken during pregnancy.