Douglas Macdonald, Ph.D., the Director of Drug Discovery and Development at CHDI Management, Inc., made this presentation at the sixth World Congress on Huntington's Disease, Rio de Janeiro, Brazil, September 28, 2013. Dr. Macdonald directs multiple HD drug discovery programs, including CHDI’s de novo programs and collaborations with biotechnology and large pharmaceutical companies. His primary focus is the development of huntingtin suppression therapeutics and biomarker discovery. Prior to CHDI, he was a senior research scientist in the CNS (central nervous system) Molecular and Functional Neuropharmacology group at Aventis Pharmaceuticals (now Sanofi), where he led several programs for neuropsychiatric disorders. Before that, he conducted research in the CNS Department at the Schering-Plough Research Institute (now Merck) and at Rockefeller University (Merrifield laboratory) in New York City. He received his Ph.D. in Pharmacology and Experimental Therapeutics from Boston University School of Medicine, his M.S. in Medical Sciences from the Department of Biomolecular Medicine at Boston University, and his B.S. in Chemistry from Trinity College in Hartford, Connecticut.