Are African Individuals at Higher Risk of Parkinson’s Disease?

Earlier this week, the National Institutes of Health issued a press release suggesting that people of African ancestry are at a higher risk of Parkinson’s disease. The conclusion is based on a study published in the Lancet Neurology.

The research was collaborative between the NIH, University College of London, and the University of Lagos, Nigeria. The study involved scientists from the Global Parkinson’s Genetics Program (GP2), the Black and African American Connections to Parkinson’s Study, and the International Parkinson Disease Genomics Consortium (IPDGC). Support was also provided by the Aligning Science Across Parkinson’s (ASAP) initiative and the Michael J. Fox Foundation for Parkinson’s Research (MJFF).

The genome-wide association study (GWAS) used data from several cohorts, including the GP2, IPDGC, and 23andMe. Excluding the 23andMe participants, Parkinson’s disease diagnosis was confirmed by a specialist.

“To effectively treat Parkinson’s and truly any disease, we must study diverse populations to fully understand what the drivers and risk factors are for these disorders,” said Andrew B. Singleton, PhD, director of the  NIH Intramural Center for Alzheimer’s Related Dementias (CARD) and a study author, in the NIH press release. “These results support the idea that the genetic basis for a common disease can differ by ancestry, and understanding these differences may provide new insights into the biology of Parkinson’s disease.”

Research using samples from nearly 200,000 individuals linked Parkinson’s disease risk to variations in gene encoding β-glucocerebrosidase (GBA1), a protein responsible for protein recycling. One copy of the gene caused a 1.5 times higher risk of Parkinson’s. Meanwhile, two copies increased risk by 3.5 times.

While these genes were more common in African American and Afro-Carribean participants, this protein variant is rarely found in European and Asian individuals.

“We were completely surprised. The goal of the initial analysis was to help train GP2 researchers in Nigeria and other parts of the world in how to analyze GWAS data,” said Sara Bandrés-Ciga, PhD, a staff scientist at NIH CARD and an author of the study. “The fact that the GBA1 variant had a significant association while others did not suggest that it is strongly tied to Parkinson’s disease in this population.”

Even with this data, more research is needed to evaluate the link between the variant and Parkinson’s disease. Additional insights may also provide ideas for risk management and treatment.

“Our results represent a good first step toward fully understanding the genetic and biological complexity of each individual around the world who has Parkinson’s disease,” added Singleton. “Our hope is that results like these will provide researchers a roadmap for developing new genetic treatments and therapies for Parkinson’s disease.”