Dr. Ellen Sidransky is the Branch Chief of the Medical Genetics Branch and is a pediatrician and geneticist in the National Human Genome Research Institute at National Institutes of Health. Dr. Sidransky received her B.A. from Brandeis University in 1977 and her M.D. from Tulane University in 1981. She trained in pediatrics at Northwestern University, and in clinical genetics at NIH. Dr. Sidransky has been a tenured NIH investigator and Section Chief since 2000. Her research interest includes both clinical and basic aspects of Gaucher disease and Parkinson disease, studies of genotype/phenotype correlation and genetic modifiers, insights from mouse models, and novel treatment strategies. She played a lead role in establishing the association between glucocerebrosidase and parkinsonism. The author of over 250 publications, she continues to focus on the complexity encountered in “simple” Mendelian disorders, the role of lysosomal pathways in parkinsonism and the development of small molecule chaperones therapy.