Objective: To analyze the frequency of matching information provided by traditional clinical assessment, dopamine transporter (DaTscan), and skin biopsy results in patients with undiagnosed parkinsonian syndromes.

Background: The clinical diagnosis of parkinsonian syndromes remains suboptimal. Consequently, ancillary tests including imaging (DaTscan) and synuclein abnormality biomarkers (skin biopsy) can provide valuable support for a correct diagnosis. Parkinson’s Disease is characterized by asymmetrically reduced dopamine uptake on a DaTscan

and intraepidermal phosphorylated alpha-synuclein deposition, with a proximal-to-distal gradient, and decreased small nerve fiber density. In contrast, atypical parkinsonisms,

particularly multiple system atrophy, often show variable DaTscan uptake deficiencies and uniformly distributed intraepidermal P-syn deposition with intact small nerve fiber

density. The aim of this study was to assess the congruency between clinical presentations and expected biomarker results.

Method: Eighteen adults with various undiagnosed parkinsonian syndromes referred to our Movement Disorders Program were assessed using clinical evaluation

(neurological exam, UPDRS scale, response to levodopa), DaTscan, and skin biopsy. We calculated the percentage of matching diagnoses among the three modalities.

Results: Only 5/18 (28%) patients received the same diagnosis across all three diagnostic modalities. Conversely, 13/18 (72%) exhibited at least one discrepancy. In detail, 6/18 (33%) had

congruent clinical assessment and DaTscans, but inconsistent skin biopsy features. Another 2 patients (11%) showed aligned DaTscan and skin biopsy results, but inconsistent clinical diagnosis. Similarly, 2/18 (11%) patients had consistent clinical assessments and skin biopsy findings, but diverging DaTscan results. Lastly, 3/18 (17%) patients demonstrated

complete discrepancy across all diagnostic modalities. In over 50% cases, initial clinical diagnosis was re-formulated after all information was considered.

Conclusion: This data emphasizes the importance of using a combination of clinical assessment, imaging and immunohistochemical biomarkers to achieve a precise diagnosis of cases presenting as parkinsonism. The synergy between traditional clinical assessment and various diagnostic tools can improve the diagnostic accuracy of parkinsonian syndromes and ultimately enhance patient management and outcomes.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/diagnostic-mismatches-between-clinical-assessment-imaging-and-alpha-synuclein-biomarkers-in-parkinsonian-syndromes/