Study Procedure - Those selected will be required to travel to the study site a total of 3 times for 2 days each at their own expense (some assistance may be available through the Foundation for Angelman Syndrome Therapeutics, visit www.cureangelman.org). It is important that you seriously consider your ability to complete the study. The number of participants we are allowed to enroll is strictly governed and funding is limited. It is imperative data is collected from each of the 24 participants to ensure the best possible results. We do not know if your child will benefit from receiving this medication, which is why we are doing this study.