Cutaneous Phosphorylated Alpha-Synuclein in Lewy Body Dementia.

OBJECTIVE

To determine the test performance of cutaneous phosphorylated alpha-synuclein (P-SYN) in dementia with Lewy bodies (DLB), individuals with reduced Montreal Cognitive Assessment (MoCA) and healthy controls.

METHODS

This is the first subgroup analysis of the Synuclein-One study, a prospective, blinded study evaluating P-SYN detection from skin biopsies in 218 subjects with a referral diagnosis of control (N = 151) and DLB (N = 67). All subjects completed detailed examinations, questionnaires, and had skin biopsies for detection of P-SYN. DLB patients were included if meeting the 4th DLB consensus probable criteria. Control subjects, aged 40-99, had no history, examination findings, or symptoms suggestive of a synucleinopathy or neurodegenerative disease. An expert review panel, blinded to pathological data, determined the final diagnosis. Controls with reduced MoCA (MoCA < 26, N = 26) at screening were analyzed separately.

RESULTS

After expert panel review, only 50/67 patients met consensus criteria for DLB, 26/151 controls had a reduced MoCA, and 120/151 controls had a normal MoCA. The proportions of subjects with cutaneous P-SYN detected by skin biopsy were 96.0% (48 of 50) of the DLB group, 31% (8 of 26) of the controls with reduced MoCA, and 3.3% (4 of 120) of the controls with normal MoCA.

INTERPRETATION: In this prospective, blinded, cross-sectional study, a high proportion of subjects meeting clinical consensus criteria for DLB had P-SYN detected in skin biopsies. Almost 1/3 of subjects with reduced MoCA testing also had P-SYN detected. These results support a role for skin biopsy detection of P-SYN in patients with DLB.

TRIAL REGISTRATION: NCT04700722.