MTHFR 677C>T (rsRS1801133) variant is associated with hyperhomocysteinemia but not with clinical severity in patients with peripheral arterial disease.

Background: The MTHFR 677C>T variant's involvement with hyperhomocysteinemia and peripheral arterial disease (PAD) is still unclear.

Objectives: To evaluate associations between the MTHFR 677C>T (rs1801133) variant and susceptibility to and severity of PAD and homocysteine (Hcy) levels.

Methods: The study enrolled 157 PAD patients and 113 unrelated controls. PAD severity and anatomoradiological categories were assessed using the Fontaine classification and the Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC), respectively. The variant was genotyped using real-time polymerase chain reaction and Hcy levels were determined using chemiluminescence microparticle assay.

Results: The sample of PAD patients comprised 60 (38.2%) females and 97 (61.8%) males. Patients were older and had higher Hcy than controls (median age of 69 vs. 45 years, p<0.001; and 13.66 µmol/L vs. 9.91 µmol/L, p=0.020, respectively). Hcy levels and the MTHFR 677C>T variant did not differ according to Fontaine or TASC categories. However, Hcy was higher in patients with the CT+TT genotypes than in those with the CC genotype (14.60 µmol/L vs. 12.94 µmol/L, p=0.008). Moreover, patients with the TT genotype had higher Hcy than those with the CC+CT genotypes (16.40 µmol/L vs. 13.22 µmol/L, p=0.019), independently of the major confounding variables.

Conclusions: The T allele of MTHFR 677C>T variant was associated with higher Hcy levels in PAD patients, but not in controls, suggesting a possible interaction between the MTHFR 677C>T variant and other genetic, epigenetic, or environmental factors associated with PAD, affecting modulation of Hcy metabolism.