The authors say their latest gene test applies to about 12 percent of isolated cleft lip and palate, or babies born with clefts only and no other birth defects. Last year, the authors and their colleagues reported that mutations in another gene account for about 2 percent of all cases of isolated clefts, meaning researchers in the field now can collectively screen for about 15 percent of isolated cleft lip and palate, an impossibility just a few years ago. Isolated clefts account for 70 percent of all cleft lip and palate.
In the latest paper, the scientists report a so-called "haplotype" gene test, one of the first of its kind in medicine. A haplotype is the sum of several recurring variations in the usual DNA sequence of a species that are spaced out, like signposts, along a gene or chromosome. In this case, they found that distinct combinations of sequence variations in and around the gene IRF6 correlated with an increased chance that a child would be born with a cleft. IRF6, which encodes a gene-activating protein called a transcription factor, plays a role during development in orchestrating the normal formation of the lips, palate, skin, and genitalia.
"This study shows that we've reached a point where it's possible to take blood samples from parents, test certain genes, and determine whether their risk for a second child with cleft lip or palate is, say, 1 or 20 percent," said Jeffrey Murray, M. D., a scientist at the University
Contact: Bob Kuska
NIH/National Institute of Dental and Craniofacial Research