Researchers in Germany have identified a fluid biomarker for detecting Parkinson’s disease (PD) and multiple system atrophy (MSA) by measuring changes in a key brain protein.
Using a platform called the immuno-infrared sensor (iRS), researchers tested spinal fluid samples from 134 individuals and correctly identified PD and MSA cases with 97 percent sensitivity and 92 percent specificity.
The iRS test looks at the shape of the alpha-synuclein (αSyn) protein, which changes as PD and MSA develop. Normally, αSyn has a flexible structure, but in disease, it forms a more rigid, folded shape. The researchers measured this shift directly without needing special labels or chemical changes.
Samples came from two groups of patients: one group with 59 people (17 with PD, 42 controls), and the other with 75 people (40 with PD, 5 with MSA, and 30 with other brain disorders). The test measured changes in the protein’s structure and found that disease cases had a significant shift compared to controls.
The overall accuracy of the test was strong: it achieved an area under the curve of 0.90, correctly distinguishing patients from controls almost all the time. Researchers also divided results into three groups – low, intermediate, and high likelihood of disease – to better track those who might develop PD or MSA in the future.
Among those with damage to the blood–brain barrier, a marker of brain injury, 79 percent of patients tested positive for misfolding, compared to none of the healthy controls.
Unlike existing tests that only detect certain types of damaged protein, the iRS approach measures all forms, offering a broader picture of disease activity. The method also showed superior accuracy than using age and sex alone to predict disease.
The researchers plan to refine the device for ease of use in clinical practice. While larger studies are still needed, these results suggest that measuring alpha-synuclein shape changes directly could help doctors diagnose PD earlier and more accurately.
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