Genome-wide association and population-tailored polygenic risk for Parkinson’s disease in Taiwan

npj Parkinson's Disease (Nature) · 2026-05-22 · open original →

Connects: LRRK2 inhibitors ↔ LRRK2 · SNCA ↔ REM sleep behaviour disorder · LRRK2 ↔ Caffeine · LRRK2 ↔ Polygenic risk & GWAS

Reader summary

by xavier.grehant on 2026-05-25

Polygenic risk & GWAS SNCA LRRK2 REM sleep behaviour disorder LRRK2 inhibitors Mitochondrial dysfunction Caffeine VPS35 & other monogenic

Researchers in Taiwan conducted the first large-scale genome-wide association study (GWAS) of Parkinson's disease in a Taiwanese population. A GWAS is like scanning every chapter of a person's DNA instruction book across thousands of people to find stretches that appear more often in people with a disease than without it. The team compared the DNA of 2,245 people with Parkinson's to 2,268 healthy controls — all of Taiwanese ancestry — and tested roughly 7.6 million genetic variants.

The study confirmed that variants near the SNCA gene (which codes for alpha-synuclein, the protein that clumps in Parkinson's brains) and the MCCC1 gene raise disease risk in Taiwan. Crucially, the SNCA signal sits on a stretch of DNA specific to East Asians — different from the signal seen in European studies — underlining that genetic risk is not one-size-fits-all. The team also confirmed two LRRK2 gene variants common in East Asians (p.G2385R and p.R1628P) and found a striking gene-dosage effect: carrying one variant raised risk ~1.5-fold; carrying both raised it about 4-fold. A suggestive new signal at PPARGC1A — a gene governing how cells build energy in their mitochondria — also emerged but needs replication. Finally, the researchers showed that genetic risk scores (tools that add many risk variants into one number) built from European data work only modestly in Taiwanese patients (AUC 0.59), and that adding East-Asian and Taiwan-specific variants meaningfully improves accuracy (AUC 0.62).

For patients and families of East Asian ancestry, this study is a step toward genetic testing and risk tools that actually reflect their biology. The LRRK2 double-dose finding is particularly actionable: people who carry both East Asian LRRK2 variants may be priority candidates for LRRK2-targeted drugs now in clinical trials, and genetic counselling is worth discussing with a neurologist. Polygenic risk scores are not yet a standard clinical test, but this work lays the groundwork for ancestry-matched tools likely available within a few years as research matures.

What this article adds

Polygenic risk & GWAS: This first Taiwan-wide PD GWAS shows that a European-derived 90-variant polygenic risk score achieves only modest discrimination (AUC 0.59) in Taiwanese patients, while a compact 16-variant panel tailored to East Asian and Taiwan-specific loci reaches AUC 0.62 — supporting the need for ancestry-matched risk tools.
SNCA: The study identifies an East Asian–enriched SNCA risk haplotype centred on intron-4 variants (rs5860181, rs3775427) that is partially independent of the European rs356182 signal, and finds a possible secondary 5′ UTR signal (rs3756059) previously linked to REM sleep behaviour disorder — adding population-specific resolution to SNCA risk architecture.
LRRK2: Among 4,500+ Taiwanese participants, carrying both East Asian LRRK2 risk variants (p.G2385R and p.R1628P) conferred ~4.3× the Parkinson's odds of non-carriers versus ~1.5× for a single variant — the clearest gene-dosage evidence yet for these alleles, with double-variant carriers representing 0.8% of PD cases versus 0.2% of controls.
REM sleep behaviour disorder: The Taiwan GWAS independently replicates genome-wide significance for rs3756059, a 5′ UTR SNCA variant previously identified in GWAS of REM sleep behaviour disorder (RBD) and PD with RBD, raising the possibility that 5′ SNCA regulatory variation contributes to phenotypic heterogeneity including the RBD prodrome.
LRRK2 inhibitors: The gene-dosage analysis identifies double East-Asian LRRK2 variant carriers (p.G2385R + p.R1628P) as a high-risk subgroup with markedly elevated LRRK2 kinase activity (elevated pRab10 phosphorylation), making them a priority population for stratified trials of type II LRRK2 kinase inhibitors now under development.
Mitochondrial dysfunction: A suggestive GWAS signal at PPARGC1A (rs609501; OR 1.22; P=3.5×10⁻⁶) — encoding PGC-1α, a master regulator of mitochondrial biogenesis — nominates this locus as a Taiwan-relevant PD risk factor, supported by prior rare-variant data in Han Chinese and epidemiological evidence linking the PPARγ agonist pioglitazone to lower PD incidence in Taiwan.
Caffeine: The study's discussion notes published evidence that caffeine intake modifies PD risk specifically among LRRK2 variant carriers in Asian populations, flagging genotype-stratified pharmacoepidemiology of caffeine as a future research direction for this high-risk subgroup.
VPS35 & other monogenic: An intronic protective variant in VPS13C (rs12900645; OR 0.82) was identified as the lead signal within a previously described protective haplotype region, with the authors noting VPS13C encodes a lipid-transfer protein involved in lysosomal–mitochondrial homeostasis — though the signal requires replication.

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