New Genetic Associations for Parkinson’s Disease Identified

Researchers at 23andMe and Genentech have identified 17 new genetic variants associated with Parkinson’s disease, almost doubling the total number of known risk variants for the condition, which gives scientists hints at potential new targets for drugs to treat the disease.

The work is part of a multi-year collaboration between the two companies begun in early 2015 aimed at identifying new therapeutic targets for Parkinson’s.

“We are incredibly excited by these findings and their potential to lead to breakthroughs in therapeutic research and treatment for Parkinson’s disease,” said Anne Wojcicki, 23andMe’s co-founder and CEO. “The 23andMe Parkinson’s community is powered by our customers who are motivated to make a difference and see the Parkinson’s research advance.   The community is unlike any other, and it is an incredible asset for researchers to make breakthrough discoveries. These findings are a testament to both the power of the 23andMe Parkinson’s community and the company’s novel research model.”

Large Study Size

Published in the journal Nature Genetics, the study is the largest meta-analysis of Parkinson’s disease to date, using data from more than 425,000 individuals.

More than 370,000 of those individuals were 23andMe customers who consented to participate in research. About 10,000 of them have Parkinson’s disease and are part of 23andMe’s Parkinson’s Research community, which is now the largest Parkinson’s disease community for genetic research in the world. The researchers also used data from individuals that are part of PDGene, a clearinghouse for Parkinson’s related research data that also includes data from 23andMe.

In addition to identifying the 17 new risk genetic variants associated with Parkinson’s, the study confirmed many variants already known to be associated with Parkinson’s. A neurology-centric strategy was used to identify candidate genes linked to variants associated with Parkinson’s. These genes are involved in lysosomal and autophagy biology, sometimes referred to as the body’s recycling and trash collection centers. This vital process involves first a sweep of the cells by autophagosomes, which collect damaged material. Then that material is transferred to lysosomes, which either break down the material or recycle it into new structures.

Hints Concerning the Development and Progression of Parkinson’s

More recent research suggest that beyond its important recycling function, autophagy and lysosomal biology may also play important roles in regulating cell function. Last year the Japanese researcher Yoshinori Ohsumi won a Nobel Prize for his work looking at autophagy and its role in certain diseases like Parkinson’s. (Here’s more on autophagy and lysosomal biology.)

Mounting evidence suggests that this process of clearing out damaged cellular material may be impaired in patients with Parkinson’s, and that this may contribute to the development and progression of the disease. Parkinson’s disease, which affects an estimated six million people worldwide, is characterized by loss of nerve cells in various parts of the body, including dopaminergic neurons in the brainstem, an area important for the regulation of movement. The loss of neurons is associated with accumulation of insoluble abnormal forms of the protein alpha-synuclein, which make up the Lewy body deposits characteristic of Parkinson’s. These abnormal proteins are believed to impair nerve cell function and survival.

Not all candidate genes make good therapeutic targets. Most drugs are small chemical molecules and the term “druggable genome,” is often used to include those genes that make proteins whose function can be changed by the binding of drug-like small molecules.

A number of the candidate genes identified in this study — such as STK39 and ITPKB — fall into this category and may therefore represent new targets for the discovery and development of novel treatments for Parkinson’s.