Scientists May Have Found A New Trigger For Parkinson's Disease

A team of scientists appears to have unearthed a previously unknown genetic trigger for Parkinson’s disease – one much more commonly seen in people with recent African ancestry, Gizmodo reported.

They found that those who were born with one or two copies of this associated variant were noticeably more likely to develop Parkinson’s. The results highlight the value of conducting genetic research in diverse populations, the authors say.

Parkinson’s is a neurodegenerative condition that progressively worsens people’s motor function and often eventually leads to dementia. It currently affects up to a million Americans and over 8 million people worldwide. In most cases, Parkinson’s is thought to be a complex mix of genetic and environmental factors, such as age and greater exposure to certain pollutants. But there is also known mutations that substantially raise a person’s individual risk, and about 15% of all cases are thought to have a family history of Parkinson’s. 

Much of the research looking into the genetic underpinnings of Parkinson’s and other diseases has been done with largely European populations. And while we’ve learned a lot from this research, the relative lack of data on other groups means we could be missing important information. A large team of scientists from the U.S., the UK, and Nigeria decided to work together to help remedy this gap.

The Lancet posted an article titled: “Identification of genetic risk loci and causal insights associated with Parkinson’s disease in African and African admixed populations: a genome-wide association study”. From the summary:

Background

An understanding of the genetic mechanisms underlying diseases in ancestrally diverse populations is an important step towards the development of targeted treatments. Research in African and African admixed populations can enable mapping of complex traits, because of their genetic diversity, extensive population subculture, and distinct linkage disequilibrium patterns. We aimed to do a comprehensive genome-wide assessment in African and African admixed individuals to better understand the genetic architecture of Parkinson’s disease in these underserved populations.

Methods

We performed a genome-wide association study (GWAS) in people of African and African admixed ancestry with and without Parkinson’s disease. Individuals were included from several cohorts that were available as a part of the Global Parkinson’s Genetics Program, the International Parkinson’s Disease Genomics Consortium Africa, and 23andMe. 

A diagnosis of Parkinson’s disease was confirmed clinically by a movement disorder specialist for every individual in each cohort, except for 23andMe, in which it was self-reported based on clinical diagnosis. We characterized ancestry-specific risk, differential haplotype structure and admixture, coding and structural genetic variation, and enzymatic activity.

Interpretation 

Our study identified a novel genetic risk factor in GBA1 in people of African ancestry, which has not been seen in European populations, and could be a major mechanistic basis of Parkinson’s disease in African populations. This population-specific variant exerts substantial risk on Parkinson’s disease as compared with common variation identified through GWAS and it was found to be present in 39% of the cases assessed in this study.

This finding highlights the importance of understanding ancestry-specific genetic risk in complex diseases, a particularly crucial point as the Parkinson’s disease field moves toward targeted treatments in clinical trials. 

The distinctive genetics of African populations highlights the need for equitable inclusion of ancestrally diverse groups in future trials, which will be a valuable step towards gaining insights into novel genetic determinants underlying the causes of Parkinson’s disease. This finding opens new avenues toward RNA-based and other therapeutic strategies aimed at reducing lifetime of Parkinson’s disease.

Related Articles On FamilyTree.com:

Parkinson’s Disease And The Microbiome

Study Indicates Vaccine Might Help Those With Parkinson’s Disease

Researchers Seek Genetic Causes of Parkinson’s