Association of the MTHFR 677C>T Polymorphism with Obesity and Biochemical Variables in a Young Population of Mexico

BACKGROUND

Methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms have been associated with overweight people and obesity. The goal of this study was to investigate the relationship of the MTHFR 677C>T polymorphism with obesity and biochemical variables in young individuals of Mexico.

METHODS

A total of 316 young individuals were included in the study, 172 with normal weight (NW) and 144 with over weight/obesity. Body mass index (BMI) was classified as NW, overweight, and obesity. Also, waist circumference was measured. Moreover, glucose, total cholesterol, and triglycerides were determined. Genotyping for MTHFR 677C>T polymorphism was performed by the PCR-RFLP method.

RESULTS

There was no difference in the distribution of the MTHFR 677C>T polymorphism between individuals with NW and overweight/obesity; neither when they were divided by overweight vs NW, nor when we contrasted obese vs NW. However, an analysis stratified by gender showed a significant protector effect of the TT genotype against obesity in males and elevated waist circumference in females. Also, overweight/obese individuals with TT genotype had less risk of high cholesterol or triglycerides than overweight/obese subjects with the other genotypes.

CONCLUSIONS

These results suggest that the MTHFR 677T polymorphism might not be a risk factor for being overweight/obesity. Rather, on the basis of our results, this variant could be a protector effect. However, further large-scale population-based studies are still necessary to clarify the role of the MTHFR 677C>T polymorphism in overweight, obesity, and lipid profile level.

The Frequency of the 677C>T and 1298A>C Polymorphisms in the Methylenetetrahydrofolate Reductase (MTHFR) Gene in the Population

Background:

The gene for 5,10-methylenetetrahydrofolate reductase (NAD(P)H) or MTHFR gene encodes protein methylenetetrahydrofolate reductase (MTHFR), an enzyme important in folate metabolism.

Aim:

The aim of this study was to determine the frequencies of 677C>T and 1298A>C polymorphisms in the MTHFR gene of healthy subjects from the population.

Material and methods:

The blood samples were collected from 164 unrelated and healthy donors from population consisted of 98 females and 66 males. Both the MTHFR 677C>T and 1298A>C single nucleotide polymorphisms (SNPs) were analyzed by Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Linkage disequilibrium (LD) between pair of SNPs was calculated through Haploview analysis.

Results:

The frequency of MTHFR 677T allele in the population (32.62%) was in agreement with the frequency of this allele in most other populations, however, the frequency of MTHFR 1298C allele (38.41%) was higher than that reported for most other populations in the world. Haploview analysis showed a relatively strong LD between 677C>T and 1298A>C SNPs with D′ values of 0.87.

Conclusion:

Regarding the two MTHFR polymorphisms, three of the nine combined genotypes were present in 87.2% of the population. 33.54% subjects were complex heterozygous (677CT/1298AC genotype), 34.15% subjects had 677CC/1298AC and 19.51% of 677CT/1298AA genotype. The subjects with 677TT genotype had a 1298AA or 1298AC genotype while subjects with 1298CC genotype had only 677CC genotype. The subjects with 677CC/1298AA genotype were only 3.05%. We were not found triple 677CT/1298CC and quadruple 677TT/1298CC mutation suggesting decreased viability of embryos with increased numbers of mutant alleles.

Homocysteine and nitrite levels are modulated by MTHFR 677C>T polymorphism in obese women treated with simvastatin

Higher homocysteine (Hcy) levels are associated with cardiovascular risk. The aim of the present study was to evaluate the effect of simvastatin treatment on circulating Hcy levels in obese women without hypertension, diabetes or dyslipidaemia; and to determine whether the 677C>T polymorphism located in methylenetetrahydrofolate reductase (NAD(P)H) (MTHFR) gene modulates the effects of this treatment on Hcy and nitrite (as a biomarker of nitric oxide (NO) bioavailability). Twenty-five obese women (body mass index ≥ 30 kg/m(2) ) who had received 20 mg/day simvastatin for 6 weeks were enrolled in the study. Venous blood samples were collected to measure plasma biomarkers and gene polymorphisms. Simvastatin treatment significantly reduced total cholesterol, low-density lipoprotein-cholesterol, thiobarbituric acid-reactive substances, high-sensitivity C-reactive protein and Hcy, whereas nitrite levels were increased. The reduction in Hcy levels in carriers of the T allele was -20.3% compared with -9.4% in patients with the CC genotype. Importantly, before treatment, nitrite levels were significantly higher in patients with the CC genotype compared with T allele carriers, whereas after treatment these levels were similar between groups. Our findings demonstrate that obese women without comorbidities and carrying the T variant of the 677C>T polymorphism of MTHFR exhibit benefits with simvastatin treatment, mainly in terms of increased NO levels.