A meta-analysis was conducted by Zhu et al (2013) to determine the relationship between the MTHFR C677T polymorphism and the risk of Parkinson’s Disease (PD) in general populations. Case controlled samples from European and Asian populations were employed, totalling 13 studies with 1820 PD cases and 7530 healthy controls. Overall, the evidence demonstrated a significant association between the presence of the C677T mutation and the risk of PD, with the T allele of the variant increasing the risk. All studies showed PD presentation to be higher in cases in comparison to controls bar one, which used a small sample size. C677T mutation + risk of PD was overall found to be increased in European populations compared with Asian populations. However less significant results in Asian studies would likely be attributed to a much small sample size in comparison to European studies (995 Asian subjects, compared with 8355 European subjects).