This Program Announcement with Referral (PAR) seeks investigator-initiated R01 applications that propose to identify, validate and/or calibrate physiologic and/or behavioral measures in preclinical animal models of disorders associated with intellectual and developmental disabilities (IDD), particularly in the pediatric population. The announcement specifically targets the development of outcome measures or biomarkers that can serve as informative endpoints in preclinical trials of therapeutic compounds and will predict the safety and efficacy of interventions in human clinical trials for these disorders. This solicitation will focus ongoing clinical and translational research on a neglected area essential for therapy and pharmacological treatment development.