Genomic landscape of autism spectrum disorder in Brazil

Genomic studies of autism spectrum disorder (ASD) have largely excluded admixed populations. To address this gap, we characterized the genomic landscape of ASD in Brazil by combining a systematic literature review with whole-exome sequencing analysis of 441 Brazilian individuals and their families. Our analysis revealed a conclusive molecular diagnosis in 13.1% of probands. The diagnostic yield was higher among individuals with clinical features, particularly comorbid signs of intellectual disability, hypotonia, and seizures, providing a basis for prioritizing genetic testing. The sample presented a diverse ancestry, with major European, African, and Native American contributions. Notably, more than half of the identified rare risk variants were located on non-European haplotypes. Both de novo and inherited variants contributed to ASD risk, and we reinforce NPAS3 as a candidate ASD risk gene. This study provides the first comprehensive genomic overview of ASD in a large Brazilian cohort, reinforcing the critical need to include diversely admixed populations in genomic research to expand the understanding of ASD architecture and improve diagnostic strategies in resource-limited settings.