My PD Story

Exploring a Unique Genetic Risk Factor for Parkinson’s in Black and African American Populations 

Along with aging and environmental factors, genetics is one of the three major factors involved in the development and progression of Parkinson’s disease (PD). Ongoing research aims to find disease-associated gene mutations to better understand PD and how to prevent or treat it. While many critical discoveries have been made from such studies, it is important to note that the research to date has been predominantly conducted using genetic samples from those of European ancestries, leaving a gap of scientific knowledge for those people with PD of other ancestries.  

Henry Houlden, PhD, a recipient of a Parkinson’s Foundation Impact Award, will be expanding the diversity of our genetic understanding of PD by studying a newly discovered disease-associated mutation found nearly exclusively in African American and African-admixed (people of African heritage outside of Africa) populations through a fruitful partnership with Professor Njideka Ulunma Okubadejo, MBCHB, MD, FMCP, FAAN, and her team in Lagos, Nigeria, and colleagues at the National Institutes of Health in Bethesda, MD. 

The mutation in question was found when Dr. Houlden and colleagues previously performed a genome-wide association study with DNA samples from nearly 200,000 people of African American and African-admixed ancestry, approximately 1,500 of whom have PD. This type of study analyzes the entirety of each person’s DNA and highlights similarities and differences between the genes of those with and without the disease, offering potential genetic clues as to which mutations are linked to PD.  

One of the clues Dr. Houlden found was a PD-linked mutation in the DNA region that helps make an enzyme called GCase (glucocerebrosidase). While PD-linked mutations in this region have previously been found, this mutation seems to affect how the enzyme works in ways that have not been observed before in similar, European ancestry-related mutations. 

To better understand how this mutation may lead to PD, Dr. Houlden will measure various genetic and biochemical factors related to GCase in 72 blood and tissue samples from people of African American and African-admixed ancestry with and without PD. He will also use parts of those samples to create petri-dish neurons of these donors, allowing him (and future researchers) to more effectively investigate how the mutation may drive the development of PD.  

From these experiments, Dr. Houlden will generate valuable data advancing our understanding of this African-ancestry PD risk factor and contribute to new PD treatments for these underrepresented populations. 

From his lab in the University College London Institute of Neurology in the United Kingdom, Dr. Houlden is ready to continue his impactful research through Parkinson’s Foundation grant funding.  

“I am very interested in Parkinson's disease in diverse populations I think this is a major link that is missing in our research strategy and will bring significant findings important to PD across the world,” he said. “The award will also exemplify how foundations around the world, such as the Parkinson's Foundation, are funding global research and understand the need to investigate and form partnerships with diverse populations for research.” 

Meet more Parkinson’s researchers! Explore our My PD Stories featuring PD researchers.