Researchers in Sweden and Norway have identified biological markers in the blood that signal the earliest stages of Parkinson's disease, potentially allowing detection up to 20 years before motor symptoms appear. The study, published in npj Parkinson's Disease, highlights a brief window where these markers are detectable, offering hope for earlier diagnosis and treatment. Blood tests based on this discovery could enter healthcare testing within five years.
A team from Chalmers University of Technology in Sweden and Oslo University Hospital in Norway has made significant progress in early Parkinson's detection. Their research focuses on two key cellular processes: DNA damage repair and the cellular stress response. These processes show distinct patterns of gene activity in the prodromal phase of the disease, before classic symptoms like tremors and slow movements emerge.
The study reveals that by the time motor symptoms appear, 50 to 80 percent of relevant brain cells are often already damaged or lost. "By the time the motor symptoms of Parkinson's disease appear, 50 -- 80 per cent of the relevant brain cells are often already damaged or gone," says Danish Anwer, a doctoral student at Chalmers and the study's first author. This underscores the importance of catching the disease in its early, often overlooked phase, which can last up to 20 years.
Using machine learning, the researchers pinpointed a unique gene activity pattern linked to these processes, present only in early-stage patients and absent in healthy individuals or those with advanced symptoms. "This means that we have found an important window of opportunity in which the disease can be detected before motor symptoms caused by nerve damage in the brain appear," explains Annikka Polster, assistant professor at Chalmers and lead researcher.
Parkinson's affects more than 10 million people worldwide and is the second most common neurodegenerative disorder after Alzheimer's, typically starting after age 55 or 60. With aging populations, cases are projected to more than double by 2050. Currently, no cure or reliable early screening exists, and methods like brain imaging or spinal fluid analysis are not suitable for widespread use.
The blood-based approach offers a cost-effective alternative. "In our study, we highlighted biomarkers that likely reflect some of the early biology of the disease and showed they can be measured in blood. This paves the way for broad screening tests via blood samples," Polster adds. Future work will explore these mechanisms for potential treatments, including drug repurposing.
Early symptoms include REM sleep behavior disorder, reduced sense of smell, constipation, depression, and anxiety. The full study, titled "Longitudinal assessment of DNA repair signature trajectory in prodromal versus established Parkinson’s disease," was funded by organizations like the Michael J. Fox Foundation and the Swedish Research Council.
