Down syndrome or trisomy 21, the most common genetics cause for mental retardation, occurs mainly due to error during meiosis. Despite of plethora of studies the exact understanding of meiotic nondisjunction is still unclear. Some studies have suggested the role of faulty folate metabolism leads to risk of Down syndrome. Methylenetetrahydrofolate reductase (MTHFR), in human encoded by MTHFR gene, plays an important role in folate metabolism. Present study analyzed the occurrence of individual and combined MTHFR C677T and A1298C polymorphism in 32 Down syndrome, 100 other intellectually disabled (ID) and 100 healthy children from Gujarat. The genotypic analysis for MTHFR C677T and A1298C was carried out using PCR-RFLP analysis. The 677T allele frequency was observed higher in Down syndrome and intellectually disabled children as compared to control. Whereas, 1298C allele frequency was higher in intellectually disabled and lower in Down syndrome children as compared to control. The double heterozygote for C677T and A1298C observed more frequent in Down syndrome and intellectually disabled children as compared to control children.
