Text Box: METHYLENETETRAHYDROFOLATE REDUCTASE 677C>T MUTATION AND EPILEPSY Ono H, Sakamoto A, Mizoguchi N, Sakura N Department of Pediatrics, Hiroshima University School of Medicine, Hiroshima, Japan Objective: Recent studies have demonstrated a common 677C>T mutation in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene, the key enzyme in the transmethylation of homocysteine (Hcy) to methionine. This mutation causes thermolability of the enzyme and reduces the activity. Although a relationship between severe MTHFR deficiency and seizures has been reported, there are no reports of a relationship between impaired remethylation of Hcy due to the 677C>T mutation and epilspy. Methods: We compared the genotype distribution and prevalence of the mutated MTHFR allele in 90 epileptic patients and 93 healthy adult control subjects. The presence of the 677C>T mutation was investigated by amplification by polymerase chain reaction and digestion of the fragment by endonuclease Hinf I. Results: The frequency of the mutant allele was significantly higher in the symptomatic or cryptogenic epileptic patients compared with the controls (51.1 vs 36.6 %, p<0.05). There was no difference of allele frequency between idiopathic epileptic patients (41.3 %) and controls. Conclusion: Our results suggest the MTHFR 677C>T mutation might be associated with certain cause of epilepsy. 2436