Scientists say they have pinpointed a flawed gene that is a major cause of cleft lip.
A single change in a sequence of a gene called interferon regulatory factor 6, or IRF6, boosts the risk of cleft lip by 18 percent, according to an investigation led by Jeffrey Murray of the University of Iowa, in the US Midwest.
The study, published in the journal Nature Genetics, is based on research among lab animals and comparisons among groups of people with a high incidence of inherited cleft lip.
Cleft lip occurs in roughly one in every 700 births and results from a problem in facial formation in the first two months of pregnancy.
Previous research has found higher rates of the condition among Asians and Native Americans. Surgery after birth usually corrects it.