Skin Biopsy Using Immunofluorescence More Accurate Than Seed Amplification Assay in Detecting Alpha-Synuclein in RBD Patients
A study published this week in NJP Parkinson’s Disease compared two methods of detecting alpha-synuclein in patients with early-stage idiopathic REM sleep behavior disorder (iRBD), a neurodegenerative disorder that often precedes the development of Parkinson’s disease and other neurodegenerative diseases.
Immunofluorescence (IF) of skin samples, which detects and visualizes the abnormal deposition of phosphorylated alpha-synuclein within the nerves, was compared to alpha-synuclein-seed amplification assay (aSyn-SAA), which detects alpha-synuclein’s seeding activity, to determine their diagnostic accuracy in 41 patients with iRBD and 40 controls.
IF staining of phosphorylated alpha-synuclein in cutaneous nerves demonstrated 78% sensitivity and 100% specificity. aSyn-SAA of skin samples demonstrated 59% sensitivity and 82% specificity, while aSyn-SAA of cerebrospinal fluid demonstrated 67% and 72% sensitivity and specificity, respectively.
Reported side effects were orthostatic headache (17%) for the lumbar puncture and minor bleeding not requiring stricture (6%) for the skin biopsy.
“The correct in vivo diagnosis of synucleinopathies is a major challenge with prognostic and therapeutic implications, particularly in the early disease phase when the start of a specific treatment will be particularly important to prevent the effect of the underlying neurodegenerative pathological diffusion. Thus, a reliable biomarker for synucleinopathies in the early disease phase will be particularly helpful to develop a disease-modifying therapy,” noted the study authors.
