Project Summary Niemann-Pick Type C (NPC) is an autosomal recessive, lysosomal storage disorder with progressive neurodegeneration and no FDA-approved therapy. Over the past decade, our research team has dedicated efforts to establishing a robust Natural History Study along with efforts to identify biomarkers to enhance our understanding of the disease. In this project, we will leverage our complementary expertise to define a catalog of biomarkers to facilitate future clinical trials. The biomarkers that we will characterize will ultimately provide information on disease progression, prognosis, are associated with commonly affected pathways in NPC and will predict therapeutic response. Towards this goal, we will 1) prioritize and validate biomarkers that reflect neuropathological alterations, 2) identify and characterize proximal biomarkers of NPC1 then 3) investigate multiple biomarkers, representing different aspects of NPC1 neuropathology, to provide prognostic information that can be used in parental counseling and to stratify this heterogeneous disorder for therapeutic trials. Our research team’s extensive discovery efforts have revealed twelve candidate markers. Within the scope of this project is our short-term goal to evaluate these markers in a larger cohort of biospecimens using custom developed and easily transferrable methods. Our long-term goal is to utilize these biomarkers as indicators of response in future clinical trials.