Polymorphisms in MTHFR, MS and CBS genes and premature acute myocardial infarction in a Pakistani population.

High prevalence of premature coronary heart disease in Pakistanis compared to other populations points towards the genetic predisposition of this population to develop this disease. Since no investigations have been carried out in Pakistan to study the relationship of polymorphisms in genes involved in homocysteine cycle, the objective of the present study was to find out if there is any association of methylenetetrahydrofolate reductase (MTHFR) C677T, A1298C; methionine synthase (MS) A2756G; cystathionine-β-synthase (CBS) 844ins68, G919A polymorphisms with premature acute myocardial infarction (AMI) in a population of Pakistani patients with this disease. In a cross-sectional study, DNA samples of 143 AMI patients (age <45 years) and 153 healthy controls were genotyped for the above mentioned polymorphisms using PCR-RFLP methods. Plasma/serum samples of both patients and healthy controls were screened for homocysteine, folate and vitamin B12. One way ANOVA and chi-squared test were used for analysis of data. Mean plasma homocysteine levels in premature AMI patients and healthy controls were found to be 23±17.2 and 23±13.4 μmol/l, respectively which are higher than the upper normal limit of this biomarker (15μmol/l). MTHFR 677 CT genotype in healthy controls and MTHFR 677 TT genotype in AMI patients were found to have significantly increased levels of plasma homocysteine (p value <0.05), while all other polymorphisms did not show any significant difference in mean levels of homocysteine between AMI patients and healthy controls. Moreover, no association was observed between MTHFR C677T, A1298C; MS A2756C; CBS844ins68 polymorphisms and premature AMI in this population. This indicates that common polymorphisms in MTHFR, MS and CBS genes have no role in premature AMI in Pakistani population.