Real fluorescence microscopy image of neurons showing their branching connections. Neurons communicate through complex networks that are essential for brain function and development. Image credit: Manuel Schottdorf,Wikimedia Commons (CC BY-SA 4.0).
An international group of researchers has identified a previously overlooked genetic mechanism that may help explain autism in individuals who have never received a genetic diagnosis.
As reported in a Nature article published on October 14, 2026, the research was undertaken by specialists from, among others, the University of Toronto and King's College London. Microexons were one of the main topics: tiny pieces of genetic material involved in producing proteins important for the nervous system.
The scientists used extensive genetic and RNA-sequencing data to discover 1,514 new microexons that had not previously been identified, 292 of which showed different splicing patterns in neural compared with non-neural cells and tissues. Then, the authors of the research applied machine learning to find gene regions that correspond to microexon splicing.
When the model was applied to genetic data from autistic individuals and their non-autistic siblings, researchers identified 72 variants that could lead to significant changes in around 2.5% of autistic individuals in the study cohorts. Of those carrying the variants, 82% had never received a genetic diagnosis. This figure applied to the 162 carriers for whom previous genetic information was available, of whom 133 had no previously identified genetic explanation. The variants were also absent from their unaffected siblings.
With this discovery, researchers have shifted some of their attention from genetic alterations themselves to the regulatory parts of DNA. Changes in these regions can have a significant effect on the proteins produced, but this area has received relatively little attention in previous research.
There is also some supporting evidence from earlier animal studies. Research has shown that removing certain microexons can lead to autism-like behaviours in laboratory mice, although it's not yet possible to say whether the same genetic mechanism operates in humans.
The researchers also carried out laboratory experiments using human induced neurons, finding that selected genetic variants could alter microexon splicing. However, this does not establish that all 72 variants directly cause autism.
Bear in mind that the recent study is based partly on genetic data analysis, and although some of its findings were supported by laboratory experiments, more research will be needed to understand the biological effects of these variants and their potential clinical significance. Hopefully, the findings could eventually lead to genetic explanations for autism in people who have already been tested without getting definite answers.
Reference
Parada, G., et al. (2026). A microexon regulatory code reveals autism-linked genetic variation. Nature. Published 14 October 2026.
