A Randomized Double-Blind Controlled Trial of Everolimus in Children and Adolescents with PTEN Mutations is aimed at evaluating the safety of Everolimus and its effects on neurocognition in patients with PTEN mutations. Patients between the ages of 6 and 45 who meet a series of eligibility and safety criteria are eligible to participate. Participants will be randomized to receive either everolimus or placebo for the 6-month trial. Enrolling sites are Boston Children’s Hospital, Cleveland Clinic, and Stanford University. Patients will visit the study center six times throughout the 6-months, and funding is available to cover study-related costs. For more information about the study, please contact Greg Geisel at 617-919-1476 or gregory.geisel@childrens.harvard.edu.