A network approach to diagnostic biomarkers in progressive supranuclear palsy.

Diagnosis of progressive supranuclear palsy (PSP) remains challenging because of the clinical overlap with Parkinson's disease (PD). To date, disease-specific biomarkers have yet to be identified. In the absence of reliable biomarkers, we used an integrated network approach to identify genes and related biological pathways associated with PSP. We tested a highly ranked gene in cellular whole-blood samples from 122 patients enrolled in the Prognostic Biomarker Study. Biological and functional analysis identified 13 modules related to activation of leukocytes and lymphocytes, protein dephosphorylation, and phosphatase activity. Integration of these results with those from microarrays identified ptpn1 as a potential biomarker for PSP. Assessment of biomarker performance revealed that ptpn1 could be used to distinguish PSP patients from PD patients with 86% diagnostic accuracy. Ptpn1 may be a diagnostic marker useful for distinguishing PSP and PD. Further evaluation in a larger well-characterized prospective study is warranted.