Why does one Parkinson's treatment not work for all patients?

New research indicates that Parkinson’s disease may not be a single illness, but a group of different biological conditions, explaining why the same therapies do not work equally well for all patients. This was reported by Reuters.

Scientists from the Vlaams Instituut voor Biotechnologie and KU Leuven used machine learning to identify two main types and five subtypes of the disease. According to them, this discovery could pave the way for more personalized therapies in the future.

Parkinson’s disease is characterized by movement difficulties and progressive damage to the nervous system. However, it has traditionally been viewed as a single disease, even though it can be caused by mutations in many different genes.

These genetic differences can disrupt brain function in various ways. This makes developing a universal treatment extremely difficult – a drug that works for one patient may have limited or no effect on another.

According to the WHO, the number of people affected by Parkinson’s is growing rapidly. In 2019, over 8.5 million people worldwide were living with this disease.

“When doctors or patients look at the disease, they see the clinical symptoms that unite people with Parkinson’s,” explains Patrik Verstreken, the study’s lead researcher. “But at the molecular level, it is evident that they fall into different subcategories. This is important because there is no single drug that acts on all these different mechanisms.”

To investigate these differences, scientists used fruit flies with mutations in 24 genes associated with Parkinson’s. They observed their behavior over time and analyzed the data using computer algorithms to identify patterns.

“We approached this without prior expectations of how a given mutation would affect the model. We simply observed the animals’ behavior over time,” says Natalie Kempf, lead author of the study.

The results show that different genetic forms of the disease naturally group into distinct categories.

Identifying subtypes could help scientists develop more precise therapies targeted at specific patient groups.

“With these subcategories, we can look for specific biomarkers and develop drugs tailored to specific patients,” says Verstreken.

During tests of potential therapies, researchers found that a treatment that improved symptoms in one group did not work in another.

“When we applied a drug that worked for one subgroup to another, there was no effect. This shows that specific therapies can be created for individual subtypes,” he adds.

The research is in its early stages and was conducted on fruit flies, not humans. Nevertheless, the results point toward a future where Parkinson’s treatment will be more closely linked to the specific biological cause of the disease in each patient.

According to the scientists, this approach could also be applied to other complex diseases caused by a combination of genetic and environmental factors.