Prevalence of the methylenetetrahydrofolate reductase 677C > T mutation inthe Mediterranean Spanish population. Association with cardiovascular riskfactors

Methylenetetrahydrofolate reductase (MT-HFR) is a key enzyme involved in fo late metabolism. A common cytosine (C) to a thymine (T) mutation at nucleot ide 677 (677C > T) in the MTHFR gene which converts an alanine residue to a valine, has been related with several biochemical phenotypes and with card iovascular risk, depending on the population studied. Our objective was to estimate the prevalence of the 677C > T mutation in a large and randomly se lected sample (289 men and 427 women) from the Mediterranean Spanish popula tion, and to test the association between this genetic variant and some car diovascular risk factors. For both genders, the prevalence of CC, CT and TT subjects was 32.0, 52.2 and 15.8%, respectively. The frequency (95% confid ence interval) of the 677T allele was 0.44 (0.40-0.48) in men and 0.40 (0.3 7-0.44) in women. This prevalence was significantly different from other Eu ropean countries, and among the highest reported in the world for any healt hy population. We found no association between the 677C > T gene variants a nd age, body mass index (BMI), total cholesterol, low-density lipoprotein c holesterol, high-density lipoprotein cholesterol, triglycerides or diastoli c blood pressure in men and women. However, in men, a statistically signifi cant increase of systolic blood pressure with the number of mutant alleles was found (122.2 mmHg in CC, 125.1 mmHg in CT and 128.5 mmHg in TT subjects ; p for trend = 0.030). This association remained significant (p = 0.047) e ven after adjustment for age, BMI, alcohol consumption, tobacco smoking, ed ucation and physical activity.