Syn-One Test Detects Early Parkinson Risk in REM Sleep Disorder, With Todd Levine, MD

At SLEEP 2025, Todd Levine, MD, presented on a recent study that showed the Syn-One Test detected phosphorylated alpha-synuclein (P-SYN) in 75% cases of REM sleep behavior disorder (RBD).1,2 HCPLive spoke with Levine about this study, and in the first half of the interview, he discussed the significance of these findings, how the Syn-One Test works, and how skin biopsy tests may change the diagnostic workflow for patients presenting with suspected idiopathic RBD (iRBD).

The second half of the interview focused on how early P-SYN detection may prevent the development of Parkinson Disease, dementia with Lewy bodies, and multiple system atrophy.

“The ability to identify patients with iRBD opens up the possibility for disease prevention trials,” Levine said. “There are many pharmaceutical companies targeting drugs that will lower the level of synuclein. If you wait until somebody…[has] already lost 60% of the nerves in that part of the brain… that causes Parkinson's disease. It's going to be very difficult to reverse that…But imagine now you could get to a patient 10 years before their Parkinson's disease’…This really starts to open the door for disease prevention trials.”

Levine discussed practical considerations for implementing the Syn-One Test in everyday practice. He said it is easy to incorporate. The Syn-One Test, a 3-millimeter punch biopsy, measures the presence of intra-neuronal P-SYN at the neck, around the knee, and the ankle. Mostly neurologists use the test, but sometimes internal medicine doctors and dermatologists will too.

Other tests currently used to detect P-SYN have disadvantages. For instance, DaTscans take 4 – 6 hours and often require patients to stop certain medications. The other option, spinal fluid analysis, requires patients to have spinal taps which is often disliked. The Syn-One Test offers a convenient option for patients and increases assess to the early detection of this pathological protein in patients with iRBD.

“It's not a test for every patient, but I think for many patients with REM behavior disorder, we're hearing across the country that this test really gives them an understanding of what's happening to them,” Levine said. “I think that's a critical piece of how we treat our patients in 2025.”

Relevant disclosures for Levine include Biogen, UCB, Regeneron Pharmaceuticals, Janssen Research & Development, ARGENX US, Sanofi and Genzyme US Companies, Merck KGaA, Alexion Pharmaceuticals, Mitsubishi Tanabe Pharma America, and Genentech.

References

1. Levine T, Bellaire B, Gibbons C, et al. THE SYN-SLEEP STUDY: DETECTION OF CUTANEOUS PHOSPHORYLATED ALPHA-SYNUCLEIN IN REM SLEEP BEHAVIOR DISORDER. Presented at SLEEP 2025, the 39th annual meeting of the Associated Professional Sleep Societies, in Seattle.

2. CND Life Sciences’ Syn-One Test® Detects Alpha-Synuclein in Skin Biopsies of Patients with REM Sleep Behavior Disorder. CND Life Sciences. June 5, 2025. https://cndlifesciences.com/syn-sleep-baseline/. Accessed June 24, 2025.