OBJECTIVE: The purpose of this protocol is to study the natural history of Fabry disease in the different organ systems, understand its pathogenesis, and develop adequate clinical outcome measures for therapy trials. Development of sensitive outcome measures is a prerequisite of enzyme or gene replacement trials in patients with Fabry's disease. STUDY POPULATION: Patients with Fabry disease of all ages. The patients are not foregoing available treatment to participate in this protocol. Experimental treatment is not part of this study. STUDY DESIGN: Patients will typically be seen once a year at NIH. Patients will have comprehensive testing in order to evaluate the state of their health as affected by the Fabry disease. OUTCOME MEASURES: All potential clinically relevant areas will be evaluated comprehensively with a particular emphasis on the vasculopathy and the peripheral neuropathy of Fabry disease.