Motor and multisystem symptom clusters in children with Autism Spectrum Disorder (ASD): A SPARK dataset study - PROJECT SUMMARY Motor impairments are pervasive in school-age children with Autism Spectrum Disorder (ASD); however, they are often ignored and remain undiagnosed and untreated. Approximately 87% of the SPARK cohort of children with Autism Spectrum Disorder (ASD), the largest ASD cohort in the US, is at-risk for a motor impairment/DCD based on findings from the Developmental Coordination Disorder (DCD) Questionnaire (Bhat, 2020). Yet, motor impairments are not part of the diagnostic criteria or specifiers for ASD per the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-V). Although motor domain was added to the NIMH research domain criteria (RDoC) for mental disorders only last year, motor issues have not been discussed as part of the RDoC for ASD. It is unclear if a unique pattern of motor impairments and multisystem impairments (motor, social communication, and repetitive behavior) are present in children with ASD. Do these patterns of impairment change across the ASD spectrum for certain sub- phenotypes or are they generalized across sex, age, comorbid diagnoses, and levels of impairment? In the proposed project, we will study the associations between motor impairment, autism severity, and comorbidities in children with ASD. Specifically, we will determine the risk for motor impairment in children with ASD and how that changes with increasing social communication impairment, repetitive behavior severity, comorbidities, and levels of impairment using parent report measures: DCD-Q, Social Communication Questionnaire (SCQ), and Repetitive Behavior Scale-Revised (RBS-R). Our analyses will also provide further evidence for generalized but unique patterns of motor impairments in children with ASD and if present, the presence of multisystem symptom clusters and sub-phenotypes of ASD. We will also highlight the issue of differential access to various therapies (OT, PT, recreational) for children with ASD and how those do not relate to a child’s risk for motor impairment, thus revealing under-diagnosis and under-treatment for motor issues in ASD using PT and recreational therapies. As the COVID crisis evolves and we wait for reliable treatments and vaccines, resuming pediatric face to face research will take a long time. Using large databases such as the SPARK study dataset to answer critical research questions is therefore, timely and essential.