Summary: Researchers have identified a specific long non-coding RNA gene, PTCHD1-AS, that contributes to the core behavioral features of Autism Spectrum Disorder (ASD).
The study shows that deletions of this gene on the X chromosome selectively alter social interaction and repetitive behaviors in males while leaving learning, memory and other cognitive abilities intact. This finding helps separate the biological mechanisms behind autism’s defining behaviors from those responsible for broader developmental functions.
Key Research Findings
- A non-coding RNA discovery: PTCHD1-AS is a long non-coding RNA (lncRNA) that regulates gene activity, in contrast to roughly 100 known ASD-associated genes that primarily encode proteins.
- Behavioral specificity: X-linked deletions of PTCHD1-AS increase ASD susceptibility in males. Male mice lacking this gene display normal attention and memory but show heightened repetitive behaviors and altered social interactions.
- Striatal circuitry: The researchers localized the main effects to the striatum, a brain region that helps regulate repetitive actions and certain social behaviors.
- Synaptic plasticity and myelination: Loss of PTCHD1-AS altered synaptic plasticity and changes in myelination-related pathways, affecting how neural signals are adjusted and transmitted.
- Protein kinase C connection: The behavioral effects were associated with reduced activity of conventional protein kinase C (cPKC) in a cortical-to-striatal circuit, alongside altered phosphorylation of signaling proteins.
Source: Hospital for Sick Children
A previously overlooked region of the human genome appears to shape the social and repetitive behaviors that characterize Autism Spectrum Disorder (ASD) without impairing learning or other cognitive functions, according to a major new study published in Nature.
A team led by The Hospital for Sick Children (SickKids) has identified PTCHD1-AS, an X-linked long non-coding RNA, as a contributor to increased ASD risk in males. Deletions in PTCHD1-AS were linked to changes in social behavior and increased repetitive actions while cognitive abilities remained unaffected.
Although many genes and copy-number variants are associated with ASD, most encode proteins and are tied to diverse developmental outcomes. This work narrows the biological pathways tied specifically to autism’s hallmark behavioral features, enabling more focused research on the mechanisms that drive social and repetitive traits.
“PTCHD1-AS gives us a new entry point to study the biology of ASD, sharpening our understanding of how specific biological pathways relate to key autism traits. This is essential, because no new therapeutics in clinical trials are designed to modulate the main features of ASD,” says senior author Dr. Stephen Scherer, Senior Scientist, Genetics & Genome Biology and Chief of Research at SickKids, and Director of the McLaughlin Centre at the University of Toronto.
A non-coding gene with a distinct role
Approximately one in 50 children and youth in Canada are diagnosed with ASD. Despite the range of presentations across the spectrum, differences in social interaction and repetitive behavior remain common and central to diagnosis.
Long non-coding RNAs (lncRNAs) like PTCHD1-AS modulate how other genes are expressed and have been understudied until recently. The research team focused on PTCHD1-AS because it sits near several protein-coding genes already linked to ASD and developmental disorders.
Analysis of whole-genome sequencing data from more than 9,300 individuals in large global databases revealed dozens of X-linked microdeletions implicating PTCHD1-AS in increased ASD susceptibility among males (who have a single X chromosome), whereas females typically retain a second X chromosome that can provide compensation.
Follow-up experiments in two independently generated Ptchd1-as knockout mouse lines supported these observations. Male knockout mice displayed increased repetitive behaviors and altered social interaction and communication, but they performed normally on tasks measuring learning, memory and attention.
“Our findings suggest a distinct biology for PTCHD1-AS compared with many ASD-associated protein-coding genes,” says Dr. Lisa Bradley, first author and Research Associate at The Centre for Applied Genomics (TCAG) at SickKids.
How PTCHD1-AS influences brain circuitry
To understand neural consequences of PTCHD1-AS disruption, the investigators examined molecular and physiological changes in the brain. They found that removing Ptchd1-as disrupted synaptic plasticity—the brain’s ability to adapt signal strength—in the dorsal striatum, a region rich in GABAergic neurons that is implicated in regulating repetitive behaviors.
Gene and protein expression profiles in the striatum revealed alterations in pathways related to synaptic plasticity and myelination, producing a molecular signature that can guide future investigations of how this non-coding RNA affects neural function.
Specifically, the team observed reductions in conventional protein kinase C isoforms and altered phosphorylation of signaling proteins such as SRC and GSK-3α/β, together with enhanced forms of striatal synaptic plasticity, including long-term potentiation and long-term depression. These molecular changes were traced to a cortical-to-striatal circuit and provide a mechanistic link to the behavioral outcomes.
“Combining human genetics, mouse models, multi-omics and electrophysiology, we’ve connected a non-coding gene to measurable changes in brain function,” says co-author Dr. Graham Collingridge, Senior Investigator at Lunenfeld-Tanenbaum Research Institute, Sinai Health, and Director of the Tanz Centre for Research in Neurodegenerative Diseases.
“Together, our research clarifies how distinct alterations in synaptic plasticity relate to core features of autism,” he adds.
Toward a more precise understanding of ASD biology
By linking a specific non-coding gene and its molecular pathway to social and repetitive behaviors, the study suggests mechanisms that may apply across ASD diagnoses, independent of the condition’s clinical complexity.
Future work will dig deeper into the molecular, cellular and circuit-level effects of PTCHD1-AS to pinpoint targets that drive the core behavioral features of ASD. Such targets could inform development of precision therapeutics aimed specifically at social and repetitive traits.
“Beyond significantly advancing our understanding of autism as a human condition, the study shows how small changes in DNA can influence complex human behavior,” Scherer says. “It’s striking how much of our disposition can be genetically influenced, even in traits that shape how we connect and interact.”
Funding: This research was supported by Autism Speaks, Autism Science Foundation, Canada Foundation for Innovation (CFI), Canadian Institutes of Health Research (CIHR), Genome Canada and Ontario Genomics, the Government of Ontario, Ontario Brain Institute, the Province of Ontario Neurodevelopmental Disorders (POND) Network, Simons Foundation Autism Research Initiative, University of Toronto McLaughlin Centre and SickKids Foundation.
Key Questions Answered:
A: PTCHD1-AS is on the X chromosome. Males have only one X chromosome, so a deletion directly affects gene function. Females usually have a second X chromosome that can compensate for such a loss.
A: PTCHD1-AS appears to regulate circuits in the striatum that govern social and repetitive behaviors, while leaving the brain regions and pathways that underlie learning and memory intact. This specificity explains the behavioral profile observed in the mouse models and in human genetic data.
A: Identifying a molecular pathway—centering on protein kinase C activity and synaptic plasticity—provides a focused target for future research. While clinical applications will require further study, these findings offer a promising direction for developing precision therapeutics that address core ASD traits.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- The journal paper was reviewed in full.
- Additional context was added by our staff.
About this genetics and autism research news
Author: Jelena Djurkic
Source: Hospital for Sick Children
Contact: Jelena Djurkic – Hospital for Sick Children
Image: Image credited to Neuroscience News
Original Research: Open access.
“An X-linked long non-coding RNA, PTCHD1-AS, and the core features of autism” by Clarrisa A. Bradley et al., published in Nature.
DOI: 10.1038/s41586-026-10515-6
Abstract
An X-linked long non-coding RNA, PTCHD1-AS, and the core features of autism
About 100 genes or copy-number variants are currently used in genetic testing for ASD. Most known ASD genes encode proteins and are associated with broad phenotypes that can include cognitive or medical complexities and attention-deficit hyperactivity disorder (ADHD).
The authors analyzed whole-genome sequencing data from 9,349 ASD cases and 8,332 controls and identified 27 male individuals with X-chromosome microdeletions implicating the long non-coding RNA PTCHD1-AS as an ASD-susceptibility gene (odds ratio = 2.56, P = 0.01).
Two Ptchd1-as knockout mouse models, created by disrupting a conserved exon, exhibited ASD-like features in males—specifically increased repetitive behaviors and impaired social behavior and communication—without accompanying cognitive deficits or ADHD-like behaviors.
Hippocampus-dependent synaptic function, complex learning and locomotor activity were normal in knockout mice. Native, nuclear-enriched Ptchd1-as expression was sustained from postnatal day 7 onward in the dorsal striatum, a GABAergic region implicated in ASD.
Multi-omics analysis revealed transcriptomic alterations in striatal oligodendrocytes, astrocytes and neurons affecting myelination and synaptic plasticity. Disruption of Ptchd1-as reduced conventional protein kinase C isoforms, altered SRC and GSK-3α/β phosphorylation, and enhanced striatal synaptic plasticity (long-term potentiation and long-term depression).
Collectively, these results implicate striatal molecular and circuit-level dysregulation through PTCHD1-AS in the aetiology of ASD.