Biomarker for Parkinson Disease Confirmed by Large Study

Results from an international, cross-sectional study published in The Lancet Neurology have identified a technique that could be used as a biomarker test for Parkinson disease (PD), confirming results from previous smaller studies which found an association between alpha-synuclein levels detected in cerebrospinal fluid (CSF) with PD. Currently, PD only can be diagnosed clinically based on a review of symptoms, neurologic and physical examinations, and patient history. The alpha-synuclein seed amplification assay (αSyn-SAA) amplifies very small amounts of misfolded aggregates of α-synuclein in CSF samples, enabling them to be detected and analyzed. 

The study included 1123 participants, including 545 individuals with a confirmed PD diagnosis, which represents the largest analysis to date using αSyn-SAA as a biochemical test to identify PD diagnosis. The participants were established members of the Parkinson’s Progression Markers Initiative (PPMI) study (NCT01141023) which is sponsored by The Michael J. Fox Foundation for Parkinson's Research (MJFF), with funding from industry. In addition to participants with a diagnosis of PD, the study also included people with sporadic PD from LRRK2 and GBA variants, healthy controls, prodromal patients with either REM sleep behavior disorder or hyposmia, and non-manifesting carriers of LRRK2 and GBA variants. 

Study results, as reported by the journal, showed high sensitivity for PD at 87.7% (95% CI [84.9–90.5]), and high specificity for healthy controls at 96.3% (93.4–99.2). The sensitivity in sporadic PD was 98.6% (96.4–99.4).” 

Overall, this study confirmed that the αSyn-SAA technique is highly accurate at identifying people with PD, and can identify those at risk for PD. 

While these study results are major and exciting, commentary has been reported that research still needs to be done to see whether the technique works on blood sampling, which is easier than CSF to use for clinical, in-office testing.