Exploring Genetic Differences in Parkinson’s Disease by Ancestry

By Olivia Dimmer – Aug 4, 2026 - Northwestern Medicine

A landmark international study has found that the genetic drivers of Parkinson’s disease can vary dramatically between populations, underscoring the need to include people of various ancestries in genetic research and clinical trials.

The study, published in The Lancet Neurology, analyzed genetic data from 99,783 participants in the Global Parkinson’s Genetics Program, including 58,559 people with Parkinson’s disease and 41,224 people without the disease. Investigators examined known Parkinson’s disease-causing mutations and high-risk variants across 11 ancestry groups, making it the largest and most genetically diverse Parkinson’s study conducted to date.

The findings have immediate implications for the newest generation of therapies targeting specific Parkinson’s-related genes as they move through clinical trials, said Niccolo Mencacci, MD, PhD, assistant professor in the Ken and Ruth Davee Department of Neurology’s Division of Movement Disorders, who was a co-author of the study.

“Scientists have learned a lot about the genetics of Parkinson’s disease over the past couple of decades, but there’s a big blind spot: almost all of that research has been done in people of European ancestry,” Mencacci said. “About three out of every four genetic studies of Parkinson’s disease have focused on this one group, even though Parkinson’s affects people all over the world.”  

In the study, investigators found that 2.1 percent of people with Parkinson’s carried a genetic variant known to directly cause the disease, while nearly 12 percent carried variants that increase disease risk. However, the frequency of variants differed substantially among ancestry groups. For example, disease-causing variants were identified in 10.7 percent of participants of Ashkenazi Jewish ancestry, but as few as 0.4 percent of participants of African ancestry. Based on the study data, risk-associated variants in the genes GBA1 and LRRK2 were detected in nearly 6,900 people with Parkinson’s disease.