P435: ACTC1 variants result in a phenotype resembling Noonan syndrome

Introduction: The 16p11.2 duplication syndrome is an autosomal dominant genetic condition that has a wide variable phenotype usually with minor dysmorphic features, developmental delay, and motor compromise.Few minor congenital anomalies affecting different body systems have been described in the past.We describe three related patients with 16p11.2duplication with additional medical findings.Case Presentation: The proband is a boy who was referred due to penoscrotal hypospadias and developmental delays.On initial physical exam was found to have short stature, hypotonia, minor distinctive facial features, and a sacral dimple.Brain imaging evidenced a Blake pouch cyst and vermian hypoplasia.Spinal US showed a conus medullaris at L2-L3 intervertebral disc level.The proband's older sister had developmental delay, and a normal cognitive development.Recently diagnosed with ADHD and depression.The proband's father developed blepharospasm and dystonia at age 13, then became wheelchair bound and required DBS surgery.Has a history of urinary blockage and multiple UTIs that required surgery.