Population Disparities and Genetics in Huntington's and Parkinson's Disease

This semester Dr. Mary Makarious discussed her research with the Global Parkinson's Genetic Program (GP2). Her findings focused on finding genetic diversity amongst Parkinson's disease, looking at various populations. Most of the data that is provided comes from European populations which causes generalization issues since it may be harmful to generalize that data for larger individuals who are not that of descent. Findings suggested that blue collar individuals are at higher risk of the development of Parkinson's disease. It has also been discovered males are two times more likely to develop Parkinson's as well as there being a 25% detectable hereditary component. 

 Another devastating neurological disease is Huntington's disease. Huntington's disease is a rare autosomal dominant progressive neurodegenerative disorder that affects movement, cognitive function and behavior. Unlike Parkinson's disease, Huntington's has a distinct cause of the development of the disease. This is due to a mutation in the HTT gene on chromosome 4 which results in the production of the abnormal proteins called huntingtin. Despite being a direct cause , here has been studies conducted to see if other factors may play a role in the likelihood of developing the disease.

In a study called “Mortality trends and disparities in adults with Huntington's disease in the United States” by Saeeed et al. (2024) researchers explored national mortality trends to assess demographic, and geographic disparities. Analysis was conducted from death certificates from 1999-2020 due to HD from ages 25 years and older. Age-adjusted mortality rates (AAMR’s) and Annual Percent Change (APC) were calculated in accordance to age, year, gender, race/ethnicity, and geography. It was revealed that the AAMR rate grew from 4.3 per 1,000,000 from 1999 to 6.0 per 1,000,000 in 2020. This shows there is a long term rise as well as acceleration in Huntington's mortality.  Non-Hispanic Whites had the highest percentage of HD with Non-Hispanic African Americans following and Hispanics being the lowest. Overall, the mortality of HD in U.S adults has increased specifically in the later periods of 2018. Higher mortality burden Non-Hispanic Whites, residents of rural areas and older adults.

Despite being different neurodegenerative diseases, both studies involve large scale databases as well as reveal population disparities. It has been discovered that both diseases have a race/ethnicity component depicting more research needing to be done. A gender component was also found and for both of these diseases, men are more prone to development. Huntington's research provides a clear causation and progression while Parkinson's includes methods for studying complex research and diverse populations. HD can inform mechanisms as well as biomarkers and disparities in PD while Parkinson's research can teach strategies to target complex neurodegenerative diseases which could apply to Huntington's. 

References :

Saeed H;Abdullah None;Hameed H;Maaz HM;Wasay A;Amin Z;Arshad MK;Jain H;Goyal A; “Mortality Trends and Disparities in Adults with Huntington’s Disease in the United States.” Journal of Huntington’s Disease, U.S. National Library of Medicine, pubmed.ncbi.nlm.nih.gov/39973386/. Accessed 9 Oct. 2025.

Blauwendraat, Cornelis, et al. “Tackling a disease on a global scale, the global parkinson’s Genetics Program, GP2: A new generation of opportunities.” The American Journal of Human Genetics, vol. 112, no. 9, Sept. 2025, pp. 1988–2000, https://doi.org/10.1016/j.ajhg.2025.07.014.