Non-coding DNA variants in glutamatergic neurons linked to autism-associated intellectual disability

A whole-genome sequencing study of 20,366 individuals has found that people with autism-associated intellectual disability carry an increased burden of de novo variants—new mutations not present in their parents—within cis-regulatory elements of glutamatergic neurons, the brain cells that use glutamate as their primary excitatory signal. The findings, published open access in Genome Medicine, point to the non-coding majority of the human genome as a meaningful contributor to intellectual disability.

The research team, led by Eric A. Sosa and John M. Greally with collaborators including Cathal Seoighe and Melissa J. Fazzari, analyzed whole-genome sequencing data in which 709,222 de novo variants had been identified. They compared the genomic distributions and properties of these variants in individuals with autism and intellectual disability against neurotypical study participants.

A baseline observation emerged first: de novo variants were enriched at cis-regulatory elements—DNA regions that control gene transcription—across all somatic cell types, in both neurodivergent and neurotypical groups.

The disease-relevant signal appeared when the researchers examined where variants fell relative to genes. In neurodivergent individuals, both with and without intellectual disability, de novo variants were enriched at promoter-proximal cis-regulatory elements of brain cell types specifically, and specifically at genes already implicated in autism and intellectual disability.

However, the general properties of these variants were not distinct enough on their own to explain why some individuals developed autism or intellectual disability while others did not. To dig deeper, the team performed a multivariate category-wide association study (CWAS).

That analysis revealed enrichment of de novo variants in cis-regulatory elements of glutamatergic neurons in individuals with intellectual disability. A complementary Random Forest machine-learning analysis then uncovered an increased burden of these events specifically within the intellectual disability subgroup.

The authors conclude that their findings support a model in which non-coding variants contribute to the oligogenic heritability of intellectual disability—meaning that many genes, each potentially contributing a small effect, collectively shape the trait—through influences on the transcriptional regulation of glutamatergic neurons.

The study addresses a long-standing gap. Although autism is strongly heritable and many genes have been implicated in its causation, the ability to make a clinical diagnosis in an affected individual remains limited.

The article was published on 24 October 2026 as open access research, and the version shared early is citable with a permanent DOI, subject to further edits before the final Version of Record. As with any observational genomic association study, the results describe enrichments and burdens at the group level; they identify a statistical pattern in variant distributions rather than establishing how any individual mutation causes disease.

Subject of Research: De novo non-coding variants in glutamatergic neuron cis-regulatory elements associated with autism-associated intellectual disability

Article Title: Individuals with autism-associated intellectual disability have an increased burden of de novo variants in cis-regulatory elements of glutamatergic neurons

Article References: Sosa, E. A., O’Shea, D., Rosean, S., Yoon, C., Stauber, J., Castillo, P. E., Seoighe, C., Fazzari, M. J., & Greally, J. M. (2026). Individuals with autism-associated intellectual disability have an increased burden of de novo variants in cis-regulatory elements of glutamatergic neurons. Genome Medicine. https://doi.org/10.1186/s13073-026-01810-y

Image Credits: AI Generated

DOI: 10.1186/s13073-026-01810-y

Keywords: autism, intellectual disability, de novo variants, cis-regulatory elements, glutamatergic neurons, whole-genome sequencing, non-coding DNA, oligogenic heritability, genomics, neurodevelopment, Individuals, autism-associated