👤 Guey-Jen Lee-Chen

Recently, a large-scale meta-analysis of genome-wide association study (GWAS) data identified several new risk loci that can modulate the risk of Parkinson's disease (PD). These associations have yet to be examined in PD patients in Chinese or Asian population. Because ethnic-specific effect is an important concern for GWAS analysis, we genotyped single-nucleotide polymorphisms in the new genetic loci, GCH1 (rs11158026), SIPA1L2 (rs10797576), VPS13C (rs2414739), and MIR4697 (rs329648), to investigate their associations with risk of PD in Taiwan. Another single-nucleotide polymorphism GCH1 rs7155501, previously identified by GWAS listed at the top 20 genes in PDGene database was also included. A total of 1151 study subjects comprising 598 patients with PD and 553 unrelated healthy controls were recruited. The frequency of minor allele (C allele) of GCH1 rs11158026 was found to be significantly higher in PD cases than in controls (p = 0.003). The CC genotype of rs11158026 increased PD risk compared to TT genotype (odds ratio [OR] = 1.29, 95% confidence interval [CI] = 1.09, 1.53, p = 0.004). Under additive model, the GCH1 rs11158026 increased the risk of developing PD (OR = 1.30, 95% CI = 1.10, 1.54, p = 0.002). In recessive model, the genotype TT of MIR4697 rs329648 marginally decreased the PD risk (OR = 0.62, 95% CI = 0.43, 0.90, p = 0.01). The PD patients demonstrated similar genotypic and allelic frequencies in GCH1 rs7155501, SIPA1L2 rs10797576, and VPS13C rs2414739 with the controls. These findings suggest that the GCH1 and MIR4697 but not SIPA1L2 and VPS13C are genetic loci influencing risk of PD in Taiwan. Show less

A large genome-wide association study has shown that the "leucine-rich repeat (LRR) and immunoglobulin (Ig) domain-containing, Nogo receptor-interacting protein-1 (LINGO1) gene" is associated with an increased risk for essential tremor (ET) recently. Given the clinical phenotype overlap between Parkinson's disease (PD) and ET, and LINGO1 had also been demonstrated to play roles in the structural plasticity and integrity of the DA neurons as well as survival of dopaminergic neurons in PD animal models, it has been suggested that the LINGO1 variant could be associated with PD. Here, we report the first analysis of the LINGO1 variant rs9652490 (A > G) in two independent case-control cohorts in ethnic Chinese populations involving a total of 1,305 subjects (649 PD patients and 656 controls) from Taiwan and Singapore. We were unable to demonstrate any significant association between genotype distribution and allele frequency with risk of PD in each case-control study and in the pooled analysis. Further meta-analysis including all published data and ours failed to demonstrate any modulatory role of rs9652490 GG genotype or G allele. LINGO1 variant rs9652490 (A > G) is unlikely to play a major role in PD in our Chinese populations. Show less