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Characterizing IQ Impairments in ASD and Testing Their Genetic Foundations

Half or more of all persons with an autism spectrum disorders (ASD) have an intellectual disability (ID). IQ is one of the best predictors of which individuals will respond well to current interventions. It also is a good predictor of adult outcomes.  Thus, it is important to try to understand the biological mechanisms that cause ID in order to reveal new avenues for devising effective treatments.  Dr. Schultz and colleagues published the first genetics paper using the Simons Simplex Collection (SSC) focused on the relationship between genes that confirm risk for ASD and ID (Sanders et al, 2011).  Contrary to the field’s expectation, they did not find any relationship between large genetic defects in persons with ASD and ID. In fact, the degree of ID was a poor predictor of overall genetic risk for autism.  In this project, Dr. Schultz’s group collected additional data to make a re-analysis of their initial findings more powerful.  In particular, they collected IQ data on other family members, including both parents and other siblings.  Family IQ data helps give much more precise estimates of the degree of ID in the youth with ASD. The hope was that including these data in their statistical analyses would yield much more powerful statistical analyses aimed at understanding the origins of ID in ASD.  Dr. Schultz’s group expected that a better understanding of the genetics of ID in those with ASD would reveal important clues as to biological mechanisms that can lead to innovative treatments.  All of the new IQ data collected in this study became part of the SSC and is available for future use to all investigators, enhancing the value of the important resource.