Genetic variants associated with Parkinson’s disease more common than estimated

New research has discovered that genetic variants associated with Parkinson’s disease (PD) are more common than researchers previously thought. Researchers in the Parkinson Foundation-supported GENEration PD study – which met its goal of 15,000 participants ahead of schedule this spring – found that 13% of participants have a genetic form of PD, which is an important observation in compared with long-term estimates. Results from the first 3.5 years of the study, which looked at a broad North American cohort, were published in the peer-reviewed journal Brain.

PD GENEration, which screens for clinically relevant genes associated with Parkinson’s disease, has been offered by the Parkinson Foundation since 2019 to any person with a confirmed diagnosis of PD. The study is the first of its kind to return results at scale through live genetic counseling in English or Spanish. This enables participants and doctors to make more informed decisions about their care, including enrolling in gene-specific clinical trials.

Additional key findings from the PD GENEration study published in Brain include:

• 7.7% of participants carried a GBA1 genetic mutation, 2.1% of participants carried a PRKN genetic mutation, and 2.4% of participants carried an LRRK2 genetic mutation. All participants were informed of their genetic status through the genetic counseling component of the program.
• The positivity rate for a genetic variant is significantly higher for high-risk individuals. Those with early-onset PD, high-risk ancestry (such as Ashkenazi Jews, Spanish Basques, or North African Berbers), or a first-degree relative affected by the disease had a positivity rate of 18%. The positivity rate for people without one of these risk factors was almost 10%.

• Many of these participants may qualify for precision medicine testing, demonstrating the feasibility and importance of widely offering genetic testing.

We did not expect the high rate of positivity for genetic mutations, namely almost 10% to have a positive result even without known genetic risk factors. Furthermore, the speed with which participants enrolled in PD GENEration is a testament to the interest of people with PD in obtaining data about their genetic status. Overall, the positivity rate and high interest in genotyping will hopefully translate into increased participation in observational studies and clinical trials for therapies targeting these genes, simplifying precision medicine clinical trials in PD.

Roy Alcalay, MD, MS, Associate Professor, Department of Neurology, Irving Medical Center, Columbia University

“PD GENEration is at the forefront of precision medicine and the potential for personalized therapies. In large part, this is because the Parkinson’s Foundation has recognized the importance of including genetic counseling in a research study that reveals genetic effects,” said Lola Cook, MS. , CGC, Department of Medicine and Molecular Genetics at Indiana University, who is the first author of Brain article and one of six genetic counselors participating in the study to date. “As we have seen from study enrollment numbers and research results, there is strong interest among people with PD to advance the research effort. This includes understanding the genetics of the disease, both broadly and individually. It is the idea that we all our part to move toward improved treatments and healing.”

PD GENEration continues into its next phase with the support of the Global Parkinson’s Genetics Program (GP2), a program of the Aligning Science Across Parkinson’s (ASAP) initiative. ASAP funding allows the Parkinson Foundation to accelerate the impact of the study by focusing on those historically underrepresented in research. Such improved broad-based recruitment reaches a wider and more diverse community in the United States, Canada and Latin America. The Parkinson’s Foundation aims to enroll an additional 8,000 participants, including 2,400 in Latin America, during the next phase of the study.

“PD GENEration is designed to be inclusive and accessible to all populations, with the goal of improving clinical outcomes for all. We are proud that the data we collected through PD GENEration reflect the largest and most diverse North American cohort tested ever—even though we hit our initial recruitment goal of 15,000 this spring, bigger things are on the horizon,” said James Beck, PhD, senior vice president and chief scientific officer of the Parkinson’s Foundation. “Our partnership with ASAP and the GP2 allows us to reach significantly more people, further increasing the diversity of participants. “Understanding the genetics shared by people with PD in different populations could reveal biological secrets of the disease, potentially leading to new treatments.”