No association of four candidate genetic variants in MnSOD and SYNIII with Parkinson's disease in two Chinese populations.

Background The manganese superoxide dismutase (MnSOD) gene, which encodes a chief reactive oxygen species (ROS) scavenging enzyme, has been reported to be associated with the risk of developing sporadic Parkinson's disease (PD) in some Asian races and the synapsin III (SYN3) gene with some neuropsychiatric diseases. Objective: To explore the associations between the MnSOD and SYN III variations and PD in two Chinese populations from mainland China and Singapore. Methods We recruited 2342 subjects including 1200 sporadic PD patients and 1142 healthy controls from two independent Asian countries. Using a case-control methodology, we genotyped the single nucleotide polymorphisms (SNP) in MnSOD (rs4880) and SYN III (rs3788470, rs3827336, rs5998557) to explore the associations with risk of PD. Results The results showed the genotype distributions and minor allele frequencies (MAF) of MnSOD (rs4880) and SYN III (rs3788470, rs3827336, rs5998557) were not significantly different between PD patients and healthy controls in mainland China and Singapore, as well as in merged populations. Conclusions The variations of MnSOD (rs4880) and SYN III (rs3788470, rs3827336, rs5998557) were not major risk factors for PD among Chinese, at least in our study populations.