Parkinson’s disease (PD) is a chronic and progressive neurodegenerative disorder that affects the dopamine-producing neurons in the substantia nigra of the brain. The disease is part of a wider group of disorders known as alpha-synucleinopathies, which include multiple system atrophy (MSA) and dementia with Lewy bodies (DLB). They are characterized by the clinical diagnosis of parkinsonian symptoms and significant deposition of pathological alpha-synuclein in neurons in the brain.
It is estimated that nearly one million individuals in the United States live with PD, with approximately 90,000 new diagnoses each year, a significant increase over previous estimates. There is also a tremendous cost associated with the morbidity of Parkinson’s disease. This clinical diagnosis requires ongoing monitoring to understand the disease progression and appropriate therapeutic strategy.
The most common symptoms include tremor, rigidity, bradykinesia (slowness of movement) and postural instability. TRAP is a mnemonic for these symptoms (Tremor, Rigidity, Akinesia and Postural instability). The disease manifests differently in each person, and you do not need all the clinical features to be diagnosed with Parkinson’s disease. The main symptom is bradykinesia or slow movement and one other feature. Approximately 10%-30% of people may never develop a tremor. There are also prodromal features that can occur 5 to 20 years before the initial diagnosis. The most common prodromal features include anosmia (inability to smell),constipation and depression.
People with PD are also more commonly older, with the average of diagnosis of 60 years age, and men outnumber women almost 2 to 1. Certain genetic variations are also considered a risk factor.
A genetic link to PD is more common among people diagnosed before the age of 50. However, genetic risk factors are still found in people with Parkinson’s of any age.
It is estimated that 15% of people with Parkinson’s have a family history, with 5%-10% having a direct genetic risk. However, most of the current understanding of genetics in PD is based on data from male individuals of western European descent. For proper understanding of the biological risk factors of PD in the U.S., research must include the overall integration of ethnicity and race.
Race in America is a social construct, and to date, there is no data suggesting any genetic difference among various ethnicities. It is unclear how PD genetic distribution impacts a diverse population. When incorporating research, it is imperative to have a proportional representation of the population.
Historically, Blacks or African Americans have not been included or were exploited by research that occurred within the U.S. and globally. Most notably, the “Tuskegee Study of Untreated Syphilis in the Negro Male” was developed and conducted by the United States Public Health Service and then the Centers for Disease Control and Prevention for more than 40 years.
In 1972, Peter Buxton, a public health service investigator, went to the press. Upon informing people outside of academia of the research study, congress enacted the National Research Act, which created the National Commission of Human Subjects of Biomedical and Behavioral Research. This provided people with the opportunity for informed consent.
Several other historical studies provided egregious exploitation of Black people in America in the name of research. Therefore, Black people have also hesitated to participate in ongoing clinical research trials.
This uncertainty is often seen in PD research, with higher proportions of whites with PD participating in research compared with Black people. Despite advances in understanding and treating PD, significant disparities persist within the Black and African American communities. These individuals often face delayed diagnoses and are less likely to receive specialized care.
Due to the historical context of research in America and the ongoing structural biases within the healthcare system regarding the diagnosis and management of PD, the Parkinson’s Foundation began to work in collaboration with Morehouse School of Medicine in Atlanta to increase the number of Black people undergoing PD genetic research. Morehouse School of Medicine (MSM) is a historically Black institution with a mission to improve the health and well-being of individuals and communities, emphasizing people of color and the underserved urban and rural populations throughout Georgia and the world.
The Parkinson’s Foundation launched a genetics initiative, PD GENEration: Mapping the Future of Parkinson’s Disease, offering genetic testing and counseling at no cost for people diagnosed with PD in both English and Spanish. This study aims to accelerate clinical trials and improve personalized treatment strategies. Genetic testing can reveal mutations in genes like LRRK2 and GBA1, strongly linked to Parkinson’s, potentially qualifying individuals for enrollment into targeted clinical trials.
The study is notable for its inclusivity, making a concerted effort to involve historically underrepresented groups, including Black and African American communities. By partnering with MSM and offering in-person and telehealth participation options, the study seeks to eliminate barriers to participation. This focus enhances the study’s scientific value and ensures that research benefits are distributed equitably across all communities affected by Parkinson’s.
We are continuing to recruit for this study at MSM, and anyone with a confirmed diagnosis of PD can participate. For further information, please visit www.parkinson.org/pdgeneration, email genetics@parkinson.org, or contact MSM’s research coordinator at tdurham@msm.edu.
Dr. Branson is an associate professor of neurology and program director of the neurology residency at Morehouse School of Medicine in Atlanta. She completed her medical school training at Boston University School of Medicine; an internship at the University of Pittsburgh Medical Center; and neurology residency, movement disorders and sleep medicine fellowships at Boston Medical Center. She has performed extensive research in racial disparities of Parkinson’s disease. She is the current sub-investigator for several studies understanding Parkinson’s disease.
