The purpose of this task order is to contribute to the understanding of the natural history of fragile X syndrome (FXS) across the lifespan and inform selection of health and developmental measures appropriate for future intervention and treatment studies by holding discussions to obtain individual advice and perspectives on research priorities for FXS, and by analyzing and publishing peer-review studies from data collected via CDC’s Fragile X Online Registry with Accessible Database (FORWARD) from 2011 to 2019 and related CDC-funded studies. FORWARD was originally designed to support research to contribute to: a more robust description of FXS, an informed understanding of the natural history of FXS across the lifespan, the impact of treatments and interventions on health outcomes and quality of life, and approaches to measuring cognitive and behavioral status in individuals with FXS.