Project Summary
Autism spectrum disorder (ASD) is a set of neurodevelopmental conditions that affect communication and social
interactions with restricted interests and repetitive behaviors. Although ASD has one of the highest heritability
rates of all complex disorders, and hundreds of genes are known to confer a risk for this condition, most ASD
cases remain idiopathic. A critical barrier to progress in the field is to identify additional ASD-risk genes. Since
most of the known ASD variants are biased toward coding regions, an unmet need is to evaluate the contribution
of noncoding sequences in ASD etiology, including tandem repeats (TRs) that account for ~5% of the human
genome. Recently two independent large-scale genome studies uncovered previously undetected and
predominantly noncoding TR mutations that have been suggested to account for ~4% of idiopathic ASD cases.
Although these studies opened uncharted territory by revealing numerous TR expansion mutations (TRexp) in
ASD, they were underpowered to adopt the required statistical rigor to select gene candidates for further
mechanistic studies. To overcome this critical barrier to progress in the field, we designed a framework to
investigate the contribution of noncoding TRexp in ASD etiology. Based on our considerable expertise in complex
TRexp disease mechanisms, we propose to test the central hypothesis that ASD-associated noncoding TRexp
contribute to ASD etiology by inducing pathogenic gene regulatory mechanisms that have been documented in
other TRexp disorders. We will test our central hypothesis by: (i) identifying high-confidence ASD-risk genes with
TRexp enriched in the ASD population (Aim 1); (ii) selecting TRexp based on their propensity to perturb high-
confidence ASD-risk gene transcript processing (Aim 2); (iii) testing the hypothesis that intronic TRexp alter
specific regulatory steps during ASD-risk gene RNA processing (Aim 3). The results of this proposal will
transform our understanding of ASD by addressing important problems underpinning critical barriers to progress
in the field by: (i) providing a new approach to identify high-confidence ASD-risk genes from underpowered
studies; (ii) developing specialized criteria to estimate TRexp propensity to perturb ASD-risk gene expression and
RNA processing patterns; (iii) spanning the bridge between genomic TRexp findings in the ASD population and
their mechanistic basis. In addition, this proposal is designed to: (iv) provide a high number of underrepresented
students with the opportunity to participate in high-quality computational and molecular biology research
including study execution, analysis, and reporting; (v) substantially strengthen our research environment by
enhancing the PI’s research productivity and program development. Therefore, this proposal addresses the
requirements listed for the SuRE-First Award (PAR-21-173) and also falls within the areas of priority detailed in
the NIMH Strategic Plan and the NIMH Strategic Research Priorities.