Cerebrospinal Fluid Diagnostic Test for Synucleinopathies Now Available

A new, first-in-class laboratory test (Syntap; Amprion, San Diego, CA) has become available that provides accurate measurement of misfolded α-synuclein aggregates in cerebrospinal fluid (CSF). The test is certified by Clinical Laboratory and Improvement Amendments (CLIA) and Clinical Association of Pathologists. 

This test is intended to aid diagnosis of synucleinopathies, including Parkinson disease (PD), Lewy body dementia (LBD), and multiple system atrophy (MSA). In addition, the test is 90% sensitive for α-synuclein in rapid-eye movement (REM) sleep behavior disorder (RBD), thus identifying those who have presymptomatic PD. Testing for the presence of α-synuclein-containing Lewy bodies in persons with Alzheimer disease (AD) and other neurodegenerative diseases is also validated.

Russ Lebovitz, MD, PhD and chief executive officer and cofounder of Amprion, said, “Being able to identify the presence of α-synuclein can be life changing for patients, giving them more accurate and earlier diagnosis. Although the test is not reimbursed by insurance yet, we are committed to ensuring that patients who need the test have access to it through their physicians.

Sensitivity and specificity, respectively, were 78.7% (95% CI: 0.66-0.88) and 89.5% (95% CI: 0.78-0.96) in biobank samples of people who were clinically diagnosed with PD (n=41), LBD (n=20), or no neurologic disorder (n=57). A positive predictive value (PPV) of 88.9% (95% CI: 88.9% and negative predictive value (NPV) of 79.7% (95% CI: 0.68-0.89) are similar to the known accuracy of clinical diagnosis of PD and LBD. Higher sensitivity and specificity were seen when tested on biobank samples of people diagnosed with PD using dopamine transporter (DaT) scans. 

Reproducibility and repeatability were confirmed with consecutives tests of samples. The limits of detection were approximately 44 fg/mL. This assay is able to identify different types of α-synuclein, which is currently being evaluated for the potential to distinguish MSA from LBD/PD.