Researchers at Chalmers University of Technology in Sweden and Oslo University Hospital in Norway have found signs of Parkinson's disease in blood samples taken years before the tremors and stiffness begin. The work points to a short period early on when the disease leaves clear traces in the blood, offering a chance to catch it with a routine test. The study came out this week in a medical journal focused on Parkinson's.
Background
Parkinson's disease hits about one million people in the United States alone, and millions more around the world. It starts with the slow death of brain cells that make dopamine, a chemical needed for smooth movement. By the time people notice shaky hands or stiff legs, 50 to 80 percent of those key brain cells are already gone. Doctors diagnose it based on symptoms, but that means treatment starts late, after much damage has happened.
For years, scientists have hunted for ways to spot Parkinson's earlier. They have looked at brain scans and fluid from the spine, but those methods are hard to use on everyone. They cost a lot and need special equipment. Blood tests would be different. A quick draw from the arm could screen large groups of people at low cost. Past efforts found some blood clues, but nothing reliable enough for everyday use.
This new research builds on that search. The team studied blood from people in early Parkinson's stages, before big symptoms showed up. They compared it to blood from healthy folks and those with later disease. What they found was a pattern of gene activity linked to how cells handle stress and fix their own DNA. These changes happen right at the start, when the brain is still mostly fine.
The window for these signs is narrow, just a few years long. After that, the traces fade as the disease moves deeper into the brain. Catching it in that early phase could change how doctors handle the illness.
Key Details
The study looked at blood cells called white blood cells. These cells showed shifts in genes that deal with oxidative stress, the kind of damage cells get from normal wear and tear. Parkinson's ramps that up early on. The genes also tied into DNA repair, the process cells use to patch breaks in their genetic code.
How They Found the Markers
Researchers took blood samples from over 100 people. Some had early signs like loss of smell or sleep issues that hint at Parkinson's. Others had full symptoms, and a control group had none. They measured RNA, the active form of genes, in the blood cells. A set of these RNA markers stood out in the early group but not later.
The team checked their findings across different batches of samples to make sure they held up. They also linked the blood changes to what happens in the brain during Parkinson's start. Dopamine cells in the brain face heavy stress and DNA breaks first. The blood picks up echoes of that.
"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. The study is an important step towards facilitating early identification of the disease and counteracting its progression before it has gone this far," says Danish Anwer, a doctoral student at Chalmers University of Technology and lead author of the study.
"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: a cost-effective, easily accessible method," says another team member.
The markers are specific to that prodromal phase, the time before motor trouble. They drop off as symptoms grow. This makes the test good for screening people at risk, like those with family history or early warnings such as constipation or REM sleep problems.
What This Means
A working blood test could screen millions without invasive steps. Clinics might offer it during regular checkups for those over 50 or with risk factors. Early detection means drugs could start sooner, perhaps slowing cell loss. Current treatments ease symptoms but do not stop the disease.
The team plans to refine the test next. They want to learn more about why these gene shifts happen and build simpler ways to spot them. In five years, they expect to test the blood method in hospitals and clinics. That timeline fits with other blood tests for diseases like cancer that moved from lab to practice fast.
Longer term, the markers could guide new drugs. If they target stress and DNA repair early, they might protect brain cells. Trials for such treatments could use the test to pick patients and track results. Parkinson's affects movement first, but it also brings thinking problems, falls, and dementia later. Early action might cut those risks too.
Experts outside the team see promise. Other groups have found blood signs of Parkinson's, like damaged DNA in cell power plants called mitochondria. Those match brain changes and show up before symptoms in some cases. Combining markers could make tests even better.
Right now, no blood test diagnoses Parkinson's alone. Doctors pair symptoms with scans or dopamine tests. But for early stages, blood could fill the gap. It would help sort who needs closer watch from those who do not.
The work also spotlights the prodromal phase. Up to half of Parkinson's cases show hints years ahead, like smell loss or gut issues. A blood test could confirm if those lead to the full disease. That would let people plan, from job changes to family talks.
As research moves forward, hospitals might see these tests in routine use. For now, the findings give hope for turning back the clock on Parkinson's damage.
