Jon Hamilton, NPR, September 24, 2023
A global effort to make genetic studies more diverse has led to a discovery about Parkinson’s disease, a common brain disorder that can impair a person’s ability to move and speak.
A team that included scientists from Lagos, London and the U.S. found a previously unknown gene variant that can nearly quadruple the risk of Parkinson’s for people of African ancestry.
The finding, published in August in The Lancet Neurology, suggests that Parkinson’s may work differently in people of African, rather than European, descent. It could eventually help scientists develop a treatment specifically for people with this particular gene variant.
The discovery was made possible by a coalition of scientists dissatisfied with the way most genetic studies are conducted.
“Our basis of knowledge for genetics in Parkinson’s disease was limited to Northern European populations,” says Andy Singleton, who directs the Center for Alzheimer’s and Related Dementias at the National Institutes of Health.
This groundbreaking project has its origins in a set of genetic samples from people in Nigeria, the result of a longtime partnership between NIH scientists and Dr. Njideka Okubadejo, a professor of neurology at the University of Lagos.
But when researchers at the University of Lagos began crunching the data, they saw evidence that something might be going on with one particular gene. It’s called GBA1 and it affects a cell’s internal recycling system.
The scientists ran all the analyses again, this time including genetic data from U.S. residents of African descent. In all, they now had data from nearly 200,000 people, including about 1,500 with Parkinson’s.
And the result held up.
The gene variant was found almost exclusively in people of African descent. Those who carried a single copy of the gene were about 50% more likely to develop Parkinson’s. People with two copies saw their risk increase by nearly 400%.
In people of European descent, another variant of the GBA1 gene also raises the risk for Parkinson’s. But the variant found in people of African descent affects a different part of the gene and appears to have a different effect on cells.