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An observational genetic study published in The Lancet Neurology by Lange and colleagues characterizes how causal and risk variants for Parkinson's disease are distributed across ancestrally diverse populations. The work draws on release 11 of the Global Parkinson's Genetics Program, issued in December 2025, and covers genome sequencing, exome sequencing, and array genotyping from 144 cohorts at 129 sites. The authors note that roughly 75 percent of Parkinson's genetic research to date has centered on individuals of European ancestry.
The analysis included 99,783 individuals, comprising 58,559 with Parkinson's disease and 41,224 controls, grouped into 11 genetically inferred ancestries. About 29 percent came from populations historically under-represented in genetic research, meaning non-European and non-Ashkenazi Jewish. Variant selection followed recommendations from the Movement Disorder Society Task Force on the Nomenclature of Genetic Movement Disorders.
A causal variant was identified in 1,217 individuals with Parkinson's disease, or 2.1 percent, though the figure varied widely by ancestry. It reached 10.7 percent in the Ashkenazi Jewish group and 0.4 percent in the African group. Risk variants in GBA1 and LRRK2 appeared in 11.8 percent of individuals with disease and 8.7 percent of controls.
GBA1 variants were the most frequent finding overall and turned up in every ancestry examined, but both frequency and variant spectrum diverged sharply, from 4.1 percent in the east Asian group to 52.9 percent in the African group, where the intronic risk variant rs3115534-G predominated. The authors describe that variant as one that would have gone undetected in European-restricted research. LRRK2 showed a parallel pattern, with causal variants concentrated in the Ashkenazi Jewish and Middle Eastern groups and risk variants largely in the east Asian group. Biallelic PRKN variants, frequently deletions and duplications, appeared across every ancestry except Ashkenazi Jewish.
The authors observe that clinical trials recruiting GBA1 and LRRK2 carriers are conducted mainly in Europe and the United States, and argue that broader ancestral representation is necessary for diagnostic accuracy and for equitable access to emerging genetically informed therapies. They caution that findings were generated in a research setting and require confirmation in certified diagnostic laboratories before clinical use.
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