MOLECULAR GENETICS OF NON-SYNDROMIC CLEFTS REVISITED

Cleft of the lip and palate (CL/P) are generally divided in to two groups, isolated cleft palate and cleftwith or without cleft palate representing a heterogeneous group of disorders affecting the upper lip and the roofthe mouth. Non-syndromic cleft lip and palate incidence is 1 in 700 to 1000 live babies with ethnic and geographicvariations. Various independent association and linkage studies using different populations have identified severalloci. Numerous genes have been reported in studies demonstration associations and/or linkage of the cleft lip andpalate phenotypes to alleles of microsatellite markers and single nucleotide polymorphisms within specific genesthat regulate transcription factor, growth factor, cell signalling and detoxification metabolisms. Currently, effortsare focussed to identify the genes and genetic variations within the numerous candidate genes that have beenfound to associate with the expression of the orofacial cleft phenotype. In conclusion, the genetic basis of CL/P isstill contentious because of genetic complexity of clefting.