New genetic risk loci identified for Parkinson disease in Asian populations

1. Two novel gene loci among Asian populations were identified and associated with Parkinson disease (SV2C, WBSCR17) that had not been previously included in European loci or polygenic risk score models.

Evidence Rating Level: 2 (Good)

Parkinson disease (PD) is a leading age-related neurodegenerative disease and cause of death, resulting in over 200,000 deaths and substantial disability globally. It is a heterogenous disease with several genes and pathways are involved in its pathogenesis. This genome-wide association study (GWAS) aimed to identify novel loci for PD among Asian participants and then compare the findings to European cohorts. Data was collected from January 1, 2016 to December 31, 2018 from the following Asian countries: Singapore/Malaysia, Hong Kong, Taiwan, mainland China, and South Korea. Replication of top loci in Japanese and European samples was performed as part of this study. A total of 31,575 samples were identified with 6,724 PD cases (mean [SD] age = 64.3 [10] years, age [SD] of onset = 58.8 [10.6] years, 46.8% female) and 24,851 controls (mean [SD] age = 59.4 [11.4] years, 55% female). Eleven genome-wide significant loci were identified, two of which were novel (SV2C and WVSCR17) and nine that had been found among Europeans previously. Subsequent replication with European and Japanese groups found significant associations for SV2C (rs246814; OR 1.16, 95% CI 1.11 to 1.21, p = 1.17×10-10). However, genetic heterogeneity was found at WBSCR17 (rs9638616; I2 = 67.1%, p = 0.00340). Models of polygenic risk scores were improved in terms of the area under the curve compared to the 78 European loci on their own (difference 2.9%, p = 6.81×10-12). Overall, this study suggests that Asian populations demonstrate two novel gene loci associated with PD that could allow for better stratification of this population based on current polygenic risk scores.

Click to read the study in JAMA Neurology

Image: PD

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