When the researchers looked at the gene and nearby regions of
the chromosome, they identified a total of 36 DNA variations,
nine of which seemed to be associated with clefting. The
individual variations were then assembled into a collective
profile called a "haplotype." "What we found is that a
particular haplotype is over-transmitted in some families with
isolated clefts, suggesting a predictive association with the
birth defect, and this was true in the populations that we
analyzed from The Philippines, Denmark, and the United States."
Based on a detailed analysis of 1,316 families, the scientists
estimated that the risk of parents with this haplotype having a
second child with isolated cleft lip and palate is about 12
percent. As the researchers noted, their estimate is based on
their analysis of the families and cannot be generalized to the
broader public. "For a complex trait like cleft lip and palate,
this is a nice step forward because there may be dozens of genes
that contribute to the condition," sai