SCOTTSDALE, Ariz. – A new study offers hope for early detection of neurodegenerative diseases like Parkinson’s. Research presented at SLEEP 2025 highlights the potential of a skin biopsy test to identify individuals at risk.

The Syn-Sleep study, a 24-month longitudinal study funded by the National Institutes of Health (NIH), investigated the presence of phosphorylated alpha-synuclein (P-SYN) in skin biopsies of patients with idiopathic REM sleep behavior disorder (iRBD). The baseline results indicated P-SYN detection in 75% of iRBD patients.¹

These findings were presented at SLEEP 2025, the 39th annual meeting of the Associated Professional Sleep Societies, LLC, held in Seattle, Washington.

iRBD is a sleep disorder where individuals act out their dreams, sometimes violently.It’s considered “idiopathic” when there’s no known cause. Importantly, iRBD is recognized as an early indicator of future neurodegenerative conditions involving P-SYN.² P-SYN is a protein associated with synucleinopathies like Parkinson’s disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA).

The Syn-One Test, used in the study, measures P-SYN in skin biopsies.Previous studies showed a 95% positivity rate in patients with clinically definite synucleinopathies.⁴

The Syn-Sleep Study aims to determine if the presence and pattern of P-SYN in skin biopsies of iRBD patients can predict future progress of a synucleinopathy.¹

according to Dr. Michele Tagliati, a movement specialist at Cedars-Sinai in Los Angeles, California, “These results support evidence that iRBD is a prodromal neurodegenerative condition and suggests that a minimally invasive skin biopsy can be used to assess P-SYN status in these patients. As the field advances and there are lifestyle interventions and future drug therapies that could address diseases like PD and DLB before they fully develop, determining if an RBD patient has synuclein deposition will be increasingly crucial.”

Key Findings of the Syn-Sleep Study

• 80 patients with iRBD and no other neurodegenerative disease were enrolled.
• Subjects had iRBD symptoms for an average of 6.7 years.
• Patients with abnormal test results tended to be older and had the disease longer.
• Individuals with P-SYN in skin biopsies tended to have a greater degree of hyposmia (reduced sense of smell).
• P-SYN positivity rates did not differ based on iRBD symptom severity, autonomic symptoms, or diagnosis method.¹

Dr. Todd Levine, chief medical officer of CND Life Sciences, clinical professor at Arizona State University, and the study’s principal investigator, stated, “We are currently doing a longitudinal reassessment of these subjects to determine if quantification of P-SYN can serve as a biomarker of disease progression. The ability to detect those patients at risk opens the door for earlier disease modulation and prevention trials.”

Presentation Details

Poster presentation details are as follows:

Understanding REM Sleep Behavior Disorder and Synucleinopathies

REM sleep behavior disorder (RBD) is a sleep disorder in which you physically act out vivid, ofen unpleasant dreams with vocal sounds and sudden, often violent arm and leg movements during REM (rapid eye movement) sleep. It’s critically important to understand its connection to other neurological conditions.

Synucleinopathies are a group of neurodegenerative diseases characterized by the abnormal accumulation of alpha-synuclein protein in the brain. These diseases include Parkinson’s disease, dementia with Lewy bodies, and multiple system atrophy. The presence of phosphorylated alpha-synuclein (P-SYN) is a key marker in diagnosing these conditions.

About the Syn-Sleep Study

The syn-Sleep Study is focused on the rate of P-SYN deposition in patients with iRBD. This NIH-sponsored study is being conducted at 11 sites across the U.S. to assess if cutaneous P-SYN can predict future development of synucleinopathy. Participating sites include Banner Health, Cedars-Sinai, Intrepid Research, Kentucky Neuroscience Institute, Lehigh Valley MD Frist Research, Movement Disorder Center of Arizona, Stanford University Mt. sinai, Texas Institute for Neurological Disorders, and University of Minnesota.