MTHFR 677TT Alone and IRF6 820GG Together with MTHFR 677CT, but Not MTHFR A1298C, Are Risks for Nonsyndromic Cleft Lip with or without Cleft Palate in an Indian Population

Aim: To determine the association of three SNPs, IRF6 G820A, MTHFR C677T, and MTHFR A1298C, with nonsyndromic cleft lip with or without cleft palate (NSCL/P) in an Indian population. Method: A total of 323 NSCL/P patients, 116 of their mothers, 108 of their fathers, and 214 normal controls have been examined for the above three SNPs. Result: Frequency of IRF6 GG was 65% in controls, 78% in cases, 84% in case-fathers, and 80% in case-mothers. MTHFR 677T homozygosity was lower than 1% in controls and unaffected parents, while in the group of probands it was much higher (3.4%; OR 4.30). The frequency of CT genotype was also high in the cases and case-mothers (OR 1.89 and 2.2, respectively). MTHFR A1298C did not reveal a statistically significant deviation in allele and genotype frequencies. Conclusion: While MTHFR 677T homozygotes show a significant association with NSCL/P, heterozygotes 677CT are minor risk factors. MTHFR A1298C does not show a risk in any combination of alleles. IRF6 820GG too forms a minor risk. However, combined genotypes IRF6 GG/MTHFR 677CT together form greater risk for NSCL/P.