Non-syndromic cleft lip with or without cleft palate in Asian populations: Association analysis on three gene polymorphisms of the folate pathway

Objective Orofacial clefts (OFCs) are one of the most common birth defects in humans. They are the subject of a number of investigations aimed at elucidating the bases of their complex mode of inheritance involving both genetic and environmental factors. Genes belonging to the folate pathway have been among the most studied. The aim of the investigation was to replicate previous studies reporting evidence of association between polymorphisms of folate related genes and the occurrence of non-syndromic cleft lip with or without cleft palate (NSCL/P), using three independent samples of different ancestry: from Tibet, Bangladesh and Iran, respectively. Design Specifically, the polymorphisms rs1801133 of MTHFR, rs1801198 of TCN2, and rs4920037 of CBS, were tested. Results A decreased risk of NSCL/P was observed in patients presenting the C677T variant at MTHFR gene (relative risk for heterozygotes = 0.53; 95% confidence interval [C.I.] = 0.32-0.87). The investigated polymorphisms mapping at TCN2 and CBS genes did not provide any evidence of association. Conclusion Overall, these results indicate that NSCL/P risk factors differ among populations and confirm the importance of testing putative susceptibility variants in different genetic backgrounds.