Objective: To study the relationship between methylenetrahydrofolate reductase (MTHFR) gene and ischemic stroke.
Methods: Four hundred and fifty four ischemic stroke patients were enrolled in the study. They were divided into large artery atherosclerosis (LAA), cardioembolism (CE), small artery occlusion (SAA), stroke of other determined etiology (SOE) and stroke of undetermined etiology (SUE) according to TOAST (Trail of ORG 10172 in Acute Stroke Treatment) criteria; and they were divided into mild, moderate and severe types ischemic stroke according to their scores of neurologic impairment. Three hundred and thirty four subjects, in whom hypertension, coronary heart disease, cerebral vascular disease, diabetes mellitus, cancer, renal failure etc. were excluded, served as controls in the study. Their C677T polymorphisms of MTHFR gene were determined with polymerase chain reaction (PCR) and denaturing high performance liquid chromatography (DHPLC), and their risk factors of ischemic stroke were recorded at the same time.
Results: The frequencies of CC, CT and TT genotype in ischemic stroke were 51.8%, 40.5% and 7.7%, respectively, and they were 56.9%, 38.3% and 4.8% respectively in controls. TT genotype and T allele were associated with LAA and CE, moderate type and severe type of ischemic stroke. The frequencies of TT genotype and T allele in ischemic stroke patients were significantly higher in those with smoking, alcohol abuse or diabetes mellitus than those in controls (all P<0.10), but CC genotype and C allele were significantly lower in them than those in controls (all P<0.05). On the other hand, all of genotypes and alleles in ischemic stroke patients with no history of smoking, alcohol abuse or diabetes mellitus were not significantly different from those in controls.
Conclusion: TT genotype and T allele are risk factors for ischemic stroke. It exists interactions between smoking, alcohol abuse, diabetes mellitus and MTHFR gene in the pathogenesis of ischemic stroke.