MTHFR C677T GENE MUTATION ASSOCIATED WITH SEVERE RISK FOR MENTAL RETARDATION IN CHILDREN

MTHFR gene polymorphism regulate folate metabolism, required for normal development of central nervoussystem and any error in metabolism either due to hereditary or sporadic gene mutation in the family lead to the developmentof mental retardation in heterozygous condition. In the present study the five families having severe congenital mentalretardation was evaluated for C677T genotype variations i.e. CC, CT & TT in probands, mother & father using PCR-RFLPanalysis. Highest frequency (60%) was observed in heterozygous condition in the mother of proband. Statistical analysisshowing significant difference (p=0.024) were observed in the father of the proband. Interestingly, the insertion of 68bp ofCβS gene mutation was also observed in father of one family suggesting paternal or maternal factors influencing for severemental retardation in children of consanguineous families as an independent risk factor. However, the high degree of geneticheterogeneity is quite striking because of severe mutation in two families. The pedigree analysis showing that the severityof disease transmission probably due to the penetrance of gene and their mode of inheritance is autosomal recessive innature.