RIT2 variant is not associated with Parkinson's disease in a Taiwanese population

Association of RIT2 and RAB7L1 with Parkinson's disease: a case-control study in a Taiwanese cohort and a meta-analysis in Asian populations

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.

Ras-like without CAAX 2 (RIT2): a susceptibility gene for autism spectrum disorder

Ras-like without CAAX2 (RIT2) which encodes a GTP-binding protein has recently been reported as a new susceptibility gene for Autism Spectrum Disorders (ASD) in a genome-wide association study. Since the gene is suggested to be involved in the pathogenesis of different neurological diseases, we investigated the association of two single nucleotide polymorphisms (SNP) rs16976358 and rs4130047 of this gene with ASD in Iranian patients. A total of 1004 individuals, comprising 532 ASD cases and 472 healthy subjects participated in this study. Allele frequency analyses showed significant over-presentation of rs16976358-C allele in cases versus controls (P < 0.0001). In addition, rs16976358 CC genotype (OR (95% CI) =3.57(1.72-7.69) and P < 0.0001) and rs4130047 CC genotype (OR (95% CI) =0.64(0.43-0.97) and P = 0.035) were associated with ASD in recessive inheritance model. Besides, haplotype analysis demonstrated an association between the C/T haplotype block (rs16976358/rs4130047) and ASD (OR (95%CI) = 0.44 (0.31-0.62), P < 0.0001). Altogether, our findings provided additional confirmation for the RIT2 gene participation in ASD risk and suggested the rs16976358 variant as a possible genetic risk factor for this disorder.

Genetic association of RIT2 rs12456492 polymorphism and Parkinson's disease susceptibility in Asian populations: a meta-analysis

Recent studies investigating the association of the Ras-like without CAAX 2 (RIT2) polymorphism, rs12456492, with Parkinson’s disease (PD) are controversial. We performed a meta-analysis to study the association between rs12456492 and PD susceptibility in Asian populations. Literature searches of PubMed and Embase were performed up to June 3, 2015, and the strength of the association between rs12456492 and PD was evaluated by odds ratios (OR) and 95% confidence intervals (CI). Four studies conducted between 2013 and 2015, comprising 2017 PD cases and 2010 controls, were included in the meta-analysis. Significant association of rs12456492 with PD was found in the dominant (GG + AG vs. AA: OR = 1.26, 95% CI = 1.20–1.44, P = 0.00) and additive models (GG vs. AA: OR = 1.38, 95% CI = 1.03–1.83, P = 0.030). Although sensitivity analysis found that the overall result was stable only in the dominant genetic model, a publication bias was also detected. Therefore, the results should be treated with caution. The current meta-analysis suggested that rs12456492 might be associated with increased PD risk in Asian populations, but studies using larger sample sizes and different ethnic populations will be needed to further confirm this association.

The RIT2 and STX1B polymorphisms are associated with Parkinson's disease

INTRODUCTION

GWAS meta-analysis identified RIT2 rs12456492 and STX1B rs4889603 as PD susceptible loci. While proteins encoded by the genes, in particular RIT2, may involve in PD pathogenesis, the association of these two variants with PD remains to be further clarified.

METHODS

We enrolled a Chinese cohort comprising 537 PD patients and 517 controls, determined the genotypes of rs12456492 and rs4889603, and analyzed these variants in relation to PD.

RESULTS

Both rs12456492 and rs4889603 were associated with PD susceptibility (P = 0.012 and 0.03, respectively). The G allele of rs12456492 and the A allele of rs4889603 served as risk alleles toward PD. Statistical differences in genotype distribution between the patients and controls were observed both in rs12456492 (marginal, P = 0.042 for GG vs. AG vs. AA) and in rs4889603 (P = 0.021 for AA + AG vs.

GG) CONCLUSION

Our data suggest that the RIT2 and STX1B polymorphisms are associated with PD etiology. The role of RIT2 in PD pathogenesis warrants further mechanistical investigation.