Abstract: ObjectiveTo explore the relationship between methylenetetrahydrofolate reductase(MTHFR) genetic polymorphism of 677C-T and 1298A-C and congenital microtia in Chinese Han population.MethodsTotally 183 microtia patients and 188 group-matched healthy examinees were recruited from 3 hospitals in Nanjing city from 2012 through 2014.The genotyping was conducted with polymerase chain reaction and restriction fragment length polymorphism(PCR-RFLP)and DNA sequencing.Frequencies and allele distribution of MTHFR polymorphism of 677C-T and 1298A-C in the cases and controls were compared with Chi-square test.ResultsThe differences in the in MTHFR 677C-T polymorphism genotype frequencies between the cases and controls were statistically significant(all P<0.05);further gender-stratified analyses showed that MTHFR 677C-T polymorphism genotype mutation mainly increases the risk of microtia in the males.However,no significant association of MTHFR 1298A-C with microtia was observed(P>0.05).Linkage disequilibrium was found between 677C-T and 1298A-C.ConclusionThe mutation of 677C-T in MTHFR gene may be a risk factor of microtia in males.