Blood test could be used to diagnose Parkinson's earlier

The genetic analysis of a blood sample could enable the early diagnosis of Parkinson’s disease, according to an exploratory study led by researchers from the Institute for Neurosciences (IN) — a joint centre of the Miguel Hernández University (UMH) of Elche and the Spanish National Research Council (CSIC). Their work has been published in the journal Neurotherapeutics.

Affecting around 12 million people worldwide, Parkinson’s disease is the second most common neurodegenerative disorder and one of the leading causes of neurological disability. One of the most significant challenges in Parkinson’s research is achieving a diagnosis before the most severe motor symptoms emerge, as diagnosis currently begins with a clinical examination when visible symptoms first appear.

“However, tremors occur when neurological damage is already advanced and may be mistaken for other disorders,” said UHM Professor Jorge Manzanares, who leads the Translational Neuropsychopharmacology of Neurological and Psychiatric Diseases Group at IN. “Until recently, the only definitive diagnosis came from post-mortem tissue analysis, but it is crucial to develop fast, minimally invasive methods that detect the disease earlier.”

The method developed by the researchers requires only a blood draw, offering a non-invasive way to detect and monitor disease progression before major symptoms appear. The analysis, performed with equipment already available in many hospital laboratories, identifies genetic alterations associated with the disease in its earliest stages.

“The key lies in genetically analysing a type of immune cells called peripheral blood mononuclear cells,” explained first author Professor Francisco Navarrete. These cells contain genetic information, but not all genes are active at all times — some genes switch on or off depending on the body’s needs, such as during an infection or the development of a disease.

Through sequencing and bioinformatics, the researchers identified more than 20 genes whose activity was altered in untreated patients with Parkinson’s disease. “These changes are not seen in healthy individuals,” noted Marina Guillot, a predoctoral researcher who co-led the gene expression analyses. “This suggests that they could serve as reliable markers for diagnosis and also provide clues about the biological mechanisms underlying disease development and progression.”

In total, 22 genes showed differential expression between 23 Parkinson’s patients and 16 healthy volunteers. Some are involved in immune responses, supporting the hypothesis that inflammation and the immune system play a role in the disease’s development. Others are linked to molecular transport within brain tissue and iron homeostasis, processes previously associated with neurotoxicity. Beyond gene expression, the researchers detected changes in cellular pathways associated with survival, inflammation, cell death and the composition of immune cells.

“We still do not fully understand how Parkinson’s disease emerges and progresses, and current treatments have limited effects,” Manzanares noted. He said he hopes these analyses will help design more effective, personalised therapies in the future.

Image credit: iStock.com/Alexey Koza