Human genetic factors in non-syndromic cleft lip and palate: An update

Orofacial clefts, particularly non-syndromic cleft lip with or without cleft palate(CL/P) are the most common craniofacial deformities, affecting one in every 700to 1000 newborns worldwide. Numerous efforts have been made to understandthe etiology of CL/P so as to predict its occurrence and to prevent it from occurringin the future. In the recent years, advances in genetics and molecular biology havebegun to reveal the basis of craniofacial development. Various genetic approaches,including genome-wide and candidate gene association studies as well as linkageanalysis, have been undertaken to identify aetiologic factors, but results have oftenbeen inconclusive or contradictory. These results may support the presence ofaetiologic heterogeneity among populations and the presence of multiple genesinvolved in the aetiology of CL/P. Despite these difficulties, several different geneshave 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.