Researchers have discovered that a protein in urine samples correlates with the presence and severity of Parkinson's disease.
The biomarker may act as a possible guide for future clinical treatments and a monitor of the efficacy of potential new Parkinson's drugs in real time during treatment.
"Nobody thought we'd be able to measure the activity of this huge protein called LRRK2 (pronounced lark two) in biofluids since it is usually found inside neurons in the brain," said Andrew West, Professor at the University of Alabama at Birmingham in the US.
For more than five years, urine and cerebral-spinal fluid samples from patients with Parkinson's disease have been locked in freezers in the National Institute of Neurological Disorders and Stroke (NINDS) National Repository.
They were stored with the expectation they might someday help unravel the still hidden course of this slow acting neurodegenerative disease.
"New biochemical markers like the one we've discovered together with new neuroimaging approaches are going to be the key to successfully stopping Parkinson's disease in its tracks,” West said.
"I think the days of blindly testing new therapies for complex diseases like Parkinson's without having active feedback both for 'on-target' drug effects and for effectiveness in patients are thankfully coming to an end," West noted.
The findings appeared in the journal Movement Disorders.
A biomarker helps physicians predict, diagnose or monitor disease, because the biomarker corresponds to the presence or risk of disease, and its levels may change as the disease progresses.
Validated biomarkers can aid both preclinical trial work in the laboratory and future clinical trials of drugs to treat Parkinson's.