Friday, March 22, 2024

Parkinson’s detecting in a simple skin biopsy

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"A simple skin biopsy test has shown a high accuracy rate in detecting an abnormal form of alpha-synuclein, the pathological hallmark of Parkinson’s disease ...
In a paper ... results from the landmark study ... validate this cutaneous method as a reliable and convenient tool to help physicians make more accurate diagnoses of Parkinson’s and the subgroup of neurodegenerative disorders known as synucleinopathies. ...
Participants underwent three 3-millimeter skin punch biopsies taken from the neck, the knee, and the ankle. ...
Among the participants with clinically confirmed Parkinson’s disease, 93 percent demonstrated a positive skin biopsy for P-SYN. Participants with DLB and MSA tested 96 percent and 98 percent positive, respectively. One hundred percent of participants with PAF were positive for the abnormal protein. Among the controls, just over 3 percent tested positive for P-SYN — an error rate the authors suspect may indicate some of the healthy controls are at risk for a synucleinopathy. ..."

From the key points and abstract:
"Key Points
  • Question  Can skin biopsy detect phosphorylated α-synuclein in individuals with synucleinopathies such as Parkinson disease (PD), multiple system atrophy (MSA), dementia with Lewy bodies (DLB), and pure autonomic failure (PAF)?
  • Finding  In this cross-sectional study of 428 participants, the proportions of individuals with cutaneous phosphorylated α-synuclein detected by skin biopsy were 92.7% with PD, 98.2% with MSA, 96.0% with DLB, 100% with PAF, and 3.3% with no history of synucleinopathy (controls).
  • Meaning  A high proportion of individuals meeting clinical consensus criteria for PD, DLB, MSA, and PAF had a skin biopsy positive for phosphorylated α-synuclein in this study, although further research is needed to validate the findings in unselected clinical populations.
Abstract
Importance  Finding a reliable diagnostic biomarker for the disorders collectively known as synucleinopathies (Parkinson disease [PD], dementia with Lewy bodies [DLB], multiple system atrophy [MSA], and pure autonomic failure [PAF]) is an urgent unmet need. Immunohistochemical detection of cutaneous phosphorylated α-synuclein may be a sensitive and specific clinical test for the diagnosis of synucleinopathies.
Objective  To evaluate the positivity rate of cutaneous α-synuclein deposition in patients with PD, DLB, MSA, and PAF.
Design, Setting, and Participants  This blinded, 30-site, cross-sectional study of academic and community-based neurology practices conducted from February 2021 through March 2023 included patients aged 40 to 99 years with a clinical diagnosis of PD, DLB, MSA, or PAF based on clinical consensus criteria and confirmed by an expert review panel and control participants aged 40 to 99 years with no history of examination findings or symptoms suggestive of a synucleinopathy or neurodegenerative disease. All participants completed detailed neurologic examinations and disease-specific questionnaires and underwent skin biopsy for detection of phosphorylated α-synuclein. An expert review panel blinded to pathologic data determined the final participant diagnosis.
Exposure  Skin biopsy for detection of phosphorylated α-synuclein.
Main Outcomes  Rates of detection of cutaneous α-synuclein in patients with PD, MSA, DLB, and PAF and controls without synucleinopathy.
Results  Of 428 enrolled participants, 343 were included in the primary analysis (mean [SD] age, 69.5 [9.1] years; 175 [51.0%] male); 223 met the consensus criteria for a synucleinopathy and 120 met criteria as controls after expert panel review. The proportions of individuals with cutaneous phosphorylated α-synuclein detected by skin biopsy were 92.7% (89 of 96) with PD, 98.2% (54 of 55) with MSA, 96.0% (48 of 50) with DLB, and 100% (22 of 22) with PAF; 3.3% (4 of 120) of controls had cutaneous phosphorylated α-synuclein detected.
Conclusions and Relevance  In this cross-sectional study, a high proportion of individuals meeting clinical consensus criteria for PD, DLB, MSA, and PAF had phosphorylated α-synuclein detected by skin biopsy. Further research is needed in unselected clinical populations to externally validate the findings and fully characterize the potential role of skin biopsy detection of phosphorylated α-synuclein in clinical care. "

Parkinson’s warning in skin biopsy — Harvard Gazette Medical office procedure identifies key biomarker that may lead to more reliable diagnosis of neurodegenerative disorders

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