Approximately 40% of new drugs approved in the last three years were approved for rare or orphan diseases. This symposium will inform the audience of the challenges, promises, and lessons learned from orphan disease investigations. We will focus on how preclinical drug development findings translated into clinical opportunities. Topics to be covered include an overview of regulatory challenges and benefits associated with orphan drug development followed by presentations on Spinal Muscular Atrophy, Huntington Disease, RETT syndrome, Amyotrophic Laterals Sclerosis. Presentations will include examples of successful translation of animal models to recently approved therapies and lessons learned along the way.