Overview
- - An international consortium reports that DOPA decarboxylase in cerebrospinal fluid is a reliable lab marker for Parkinson’s disease and dementia with Lewy bodies.
- - The enzyme’s levels ran up to about 2.5 times higher than in healthy people and about 1.9 times higher than in Alzheimer’s, delivering diagnostic accuracy above an AUC of 0.9.
- - Researchers built two quantitative immunoassays and confirmed performance across large, diverse cohorts, including clinical groups (n≈740), a biologically defined set (n≈253), a dopamine-transporter imaging cohort (n≈102), and autopsy-confirmed cases (n≈78).
- - Autopsy work linked higher CSF DDC to advancing α‑synuclein pathology and showed the enzyme co-locates with α‑synuclein in the substantia nigra, tying the signal to disease biology rather than a nonspecific change.
- - Clinically, the marker was associated with the presence of motor symptoms but not their severity, and experts say a standardized test could reduce harmful misdiagnoses by giving doctors an objective result early in care.