A technique that identifies the build-up of abnormal protein deposits linked to Parkinson's disease could aid in early detection and play a key role in the clinical diagnosis and characterisation of the disorder, according to a study published in The Lancet Neurology journal.
The research confirms that the technique—known as α-synuclein seed amplification assay (αSyn-SAA)—can accurately detect people with the neurodegenerative disease and suggests it can identify at-risk individuals and those with early, non-motor symptoms prior to diagnosis.
The presence of misfolded α-synuclein protein aggregates in the brain is the pathological hallmark of Parkinson's disease.
"Recognising heterogeneity in underlying pathology among patients with Parkinson's disease has been a major challenge," said study co-lead author Professor Andrew Siderowf, of the University of Pennsylvania Perelman School of Medicine, US.
"Identifying an effective biomarker for Parkinson's disease pathology could have profound implications for the way we treat the condition, potentially making it possible to diagnose people earlier, identify the best treatments for different subsets of patients, and speed up clinical trials," said Siderowf.
The authors assessed the usefulness of αSyn-SAA for identifying underlying heterogeneity in people with Parkinson's disease, and its ability to detect early signs of the condition, using data from the Parkinson's Progression Markers Initiative (PPMI) cohort.
Among the 1,123 participants in the analysis were individuals with a diagnosis of Parkinson's disease and at-risk people with gene variants (GBA and LRRK2) linked to the condition.
So-called prodromal participants were also included. These people had non-motor symptoms—sleep disturbance or loss of smell—that can be early signs of Parkinson's disease.
However, they had not been diagnosed with the disease and had none of the typical motor symptoms, such as tremors or muscle stiffness, which come later in the disease's development.
The reason to include prodromal participants was to determine whether αSyn-SAA might predict the onset of Parkinson's as well as help diagnose people with established symptoms.
Samples of cerebrospinal fluid--that surrounds the brain and spinal cord—from each participant were analysed using αSyn-SAA.
This technique amplifies very small amounts of misfolded aggregates of α-synuclein in samples from people with Parkinson's disease to the point that they can be detected using standard laboratory techniques.
Findings of the analyses confirm that αSyn-SAA identifies people with Parkinson's disease with high accuracy, with positive results in 88 per cent of all participants with a diagnosis, the researchers added.