phenotypic manifestations in their relatives, explore the natural history and extent of associated clinical manifestations. We also want to investigate pre-motor manifestations in subjects at higher risk for developing parkinsonism that could contribute to earlier diagnosis. Participants will be evaluated at the NIH to better characterize the clinical, genetic and pathophysiological features of these disorders. In order to better understand the entire effect of the enzyme deficiencies and the function of the specific proteins involved, emphasis will be placed on individuals with atypical presentations. In particular, we will focus on subjects with Gaucher disease and parkinsonism, to better understand the association between the two disorders. Following an initial comprehensive workup, participants will be studied either in the inpatient wards or the outpatient clinic, and will be re-evaluated at periodic intervals longitudinally.