Methylenetetrahydrofolate Reductase (MTHFR) C677T Polymorphism and Subacute Combined Degeneration: Revealing a Genetic Predisposition

Abstract

Vitamin B12 deficiency is regarded as the prevailing cause of subacute combined degeneration of the spinal cord (SCD). Nevertheless, the genetic predisposition to SCD remains unclear. The aim of this study was to explore the association between methylenetetrahydrofolate reductase gene (MTHFR) C677T polymorphism and SCD. We investigated MTHFR C677T polymorphism in SCD patients and found that the distribution of MTHFR C677T genotypes was significantly different between SCD patients and age-matched controls. Furthermore, the T allele frequency was markedly increased in SCD compared with the controls. In addition, the plasma homocysteine concentrations in subjects with the TT genotype were significantly elevated compared to those with the CC genotype. Logistic regression analysis results revealed that the MTHFR C677T genotype (TT vs. CT and CC) and vitamin B12 deficiency were risk factors for SCD. Our findings indicate that the T allele of the MTHFR C677T confers a strong genetic predisposition to SCD and provide evidence of an association between MTHFR C677T polymorphism and SCD. These data reveal a potential mechanism underlying SCD.

Keywords: homocysteine; methionine; methylenetetrahydrofolate reductase gene; subacute combined degeneration; vitamin B12.

Figure 1

Correlation between the plasma concentrations of folate and vitamin B12 with homocysteine levels. (A) The linear correlation between homocysteine and vitamin B12 concentrations in the SCD group. Plasma homocysteine and vitamin B12 concentrations exhibited a negative linear correlation in the SCD group (r_s = −0.463, P = 0.009). (B) The linear correlation between homocysteine and vitamin B12 concentrations in the control group. Plasma homocysteine and vitamin B12 concentrations exhibited a negative linear correlation in the control group (r_s = −0.314, P = 0.005).

Figure 2

The linear correlation between homocysteine and folate concentrations. Homocysteine and folate concentrations did not exhibit a linear correlation (r_s = 0.009, P = 0.924).