Several genome-wide association studies and meta-analyses on Parkinson's disease (PD)-related genes have identified several risk foci in Ras-related genes, particularly among Caucasian individuals. However, the corresponding results have been controversial among Asian individuals. We investigated whether 2 single-nucleotide polymorphisms of Ras-related genes, RIT2 (rs12456492) and RAB7L1 (rs823118), are associated with PD risk in Taiwanese individuals. In addition, we conducted a meta-analysis of all studies related to rs12456492 in Asian populations to resolve inconsistency in this locus. In total, 1103 Taiwanese individuals (588 patients with PD and 515 controls) and 1111 Taiwanese individuals (594 patients with PD and 517 controls) were genotyped for rs12456492 and rs823118. However, we could not confirm the association of rs12456492 and rs823118 with PD. Our current meta-analysis involving the rs12456492(A/G) variant demonstrated that the GG + GA genotypes, GG genotypes, and G allele may be risk factors for PD. RIT2 may increase PD risk in Asian individuals. The discrepancies between Caucasian and Asian populations may be due to differences in geographic region-specific genetic backgrounds and gene-environmental interactions.
Keywords: Disease association; Parkinson's disease; Polymorphism; RAB7L1; RIT2; Ras-related gene.
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