The 5,10-methylenetetrahydrofolate reductase (MTHFR) gene has been reported to be a candidate gene for susceptibility to Parkinson's disease (PD), but results of different studies are conflicting.
Our results suggested that the T allele of rs1801133 variant and A-T haplotype of rs1801131-rs1801133 in the MTHFR gene may decrease the risk of developing PD in Chinese Han population from mainland China.
Variants in the Quinoid Dihydropteridine Reductase NM_000320 (QDPR c.68G > A (p.G23D)), Sepiapterin Reductase NM_003124 (SPR c.596-2A > G) and Methylenetetrahydrofolate Reductase NM_005957 (MTHFR c.677C > T and c.1298A > C) genes are frequent in Malta and potential candidates for PD.
The C677T single-nucleotide polymorphism in the methylenetetrahydrofolate reductase gene (MTHFR) may elevate homocysteine (Hcy) levels and increase the risk of Parkinson's disease (PD); however, results are conflicting.
Collectively, our meta-analysis suggests that rs1801133 is significantly associated with susceptibility to PD in European and Asian populations, and MTHFR is likely an authentic risk gene for PD.
However, COMT: rs4680: A>G and rs4633: C>T polymorphisms were found to significantly affect PD risk, and the MTHFR 677C>T polymorphism helped determine plasma Hcy concentrations.
Our findings provide support for the synergistic effects of polymorphisms in the folate metabolic pathway genes in PD susceptibility; the increased PD risk would be more significant in carriers with the polymorphisms of MTHFR, MTR, and MTRR genes.
In AD there were significant differences of the levels of only Cys (GG, MTHFR, G1793A) and Met/Hcy (AA, MTHFD1, G1958A) whereas in PD there were more significant differences of the levels of thiols: Hcy [MTHFR: CT (C677T) and GG (G1793A); MTR, AG (A2756G)], Met [MTR, AA (A2756G)], Cys [MTR, AG (A2756G)], and Met/Hcy [MTHFR: CC, CT (C677T) and AA (A1298C), and GG (G1793A); MTHFD1 AA(G1958A); MTR AA(A2756G)].
In conclusion, results of the study revealed that the MTHFR C677T polymorphism could significantly influence age at onset of PD in Chinese population, but neither as a genetic susceptibility nor as a predictor of levodopa-induced adverse effects in PD.
In a prospective, population-based cohort study among 5,920 participants aged 55 years or older, we observed that the TT variant of the methylenetetrahydrofolate reductase C677T polymorphism is associated with an increased risk for Parkinson's disease in smokers.
In a prospective, population-based cohort study among 5,920 participants aged 55 years or older, we observed that the TT variant of the methylenetetrahydrofolate reductaseC677T polymorphism is associated with an increased risk for Parkinson's disease in smokers.
Certain mutations (TT homozygous; CT heterozygous; CC wild-type) of the methylenetetrahydrofolate (MTHFR) gene and long-term levodopa application in patients with Parkinson's disease (PD) support onset of hyperhomocysteinemia.