Genetics of cleft lip and palate : a review.

Orofacial clefts, particularly non-syndromic cleft lip with or without cleft palate (CL/P) are the most common craniofacial deformities, affecting one in every 700 to 1000 newborns worldwide. Numerous efforts have been made to understand the etiology of CL/P so as to predict its occurrence and to prevent it from occurring in the future. In the recent years, advances in genetics and molecular biology have begun to reveal the basis of craniofacial development. Various genetic approaches, including genome-wide and candidate gene association studies as well as linkage analysis, have been undertaken to identify aetiologic factors, but results have often been inconclusive or contradictory. These results may support the presence of aetiologic heterogeneity among populations and the presence of multiple genes involved in the aetiology of CL/P. Despite these difficulties, several different genes have been implicated in harbouring genes that contribute to the aetiology of CL/P. In conclusion, the genetic basis of CL/P is still controversial because of genetic complexity of clefting.