The consortium, led by Dr Katharina Bolsewig and Prof Charlotte Teunissen of the Laboratory of Neurochemistry at the UMC in Amsterdam, with the essential contribution of Dr Sebastiaan Engelborghs, Professor at the Vrije Universiteit Brussel and Head of the Department of Neurology at UZ Brussel, focused on the protein DOPA decarboxylase. This protein plays a crucial role in the production of dopamine in the brain. The study shows that the concentration of DOPA decarboxylase in cerebrospinal fluid is significantly higher in patients with Parkinson's disease or Lewy body dementia. This difference is even clearly measurable compared with patients suffering from Alzheimer's disease, making the test highly specific.
Professor Engelborghs: "The importance of this discovery for clinical practice is considerable, as dementia with Lewy bodies is often difficult to diagnose correctly at present. Because of the strong overlap of symptoms with other forms of dementia, patients are regularly misdiagnosed. Misdiagnosis can lead to less effective or, in some cases, harmful treatment. The new measurement method provides doctors with an objective tool for determining the right course of action at an early stage".
In the course of the study, the consortium developed two highly sensitive laboratory tests to reliably record the presence of DOPA decarboxylase. The results show that values in the target group are up to two and a half times higher than in healthy control subjects. In addition, a higher concentration of the biomarker correlated directly with the degree of pathological changes in the brain, underlining the biological relevance of the test.
Although these results represent a significant step towards everyday application in healthcare, the consortium stresses that further standardisation is required. "We can speak of a fruitful international collaboration. This publication brings a crucial biomarker closer to the patient, precisely in cases where diagnosis is still too often associated with uncertainty," concludes Engelborghs.
The study, entitled "A quantitative DOPA decarboxylase biomarker for diagnosis in Lewy body disorders", was carried out by an international team of experts. The full results are available in Nature Medicine (2026) via DOI: 10.1038/s41591-026-04212-0.
