GCH1 p.Ser80Asn Confers Risk for Parkinson's Disease in East Asian Populations.

INTRODUCTION GCH1 has been implicated in Parkinson's disease (PD), but its risks variants and associations are not well defined.

Objectives

Our goal was to investigate the clinical relevance and PD risk associated with the GCH1 p.Ser80Asn variant.

Methods

We first identified a segregating GCH1 p.Ser80Asn variant in a Malaysian Chinese PD family via whole genome sequencing (WGS). We assessed its risk association using multi-ancestry WGS data from the Global Parkinson's Genetics Program (GP2) (n = 22,372PD vs. n = 8,826Controls) and meta-analysis of East Asian (EAS) cohorts (n = 4,712PD vs. 38,733Controls). Haplotype analyses were performed and clinico-demographic details of affected variant carriers were collated.

Results

The GCH1 p.Ser80Asn variant was enriched in GP2 EAS PD populations (n = 9/2,757; 0.33%), but not detected in other ancestries. Meta-analysis revealed increased PD risk in EAS populations (odds ratio = 5.1; 95% confidence intervals [CI] = 2.3-10.7; P = 2.89 × 10-5). A shared haplotype (~330 kbp) was identified among variant carriers. Affected carriers (mean age at onset: 56.3 ± 12.5 years) had additional occurrence of dystonia, whereas dementia was rare.

Conclusions

The GCH1 p.Ser80Asn variant is a rare, EAS-enriched risk variant for PD. © 2026 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. © 2026 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.