Family-based clinical associations and functional characterization of the serotonin 2A receptor gene (HTR2A) in autism spectrum disorder.
A common serotonin receptor variant is under-inherited in autism and cuts long-form mRNA, adding biological sense to rigid or anxious behavior.
01Research in Context
What this study did
The team looked at 158 families where one child has autism.
They checked who passed on the HTR2A gene variant rs6311.
They also measured how much long-form mRNA the gene made in brain tissue.
What they found
Parents gave the rs6311/A form to their kids less often than chance.
Less of the long mRNA was found in post-mortem brain samples.
Both clues point to this tiny DNA change lowering gene activity and raising autism risk.
How this fits with other research
Eussen et al. (2016) used the same family method for the oxytocin receptor gene and saw a similar small signal.
Guo et al. (2017) showed BTBR autism mice have low serotonin in the hippocampus.
The mouse data look opposite—less brain serotonin versus less receptor mRNA—but they measure different steps in the same pathway, so the papers actually agree the serotonin system is off in autism.
Why it matters
You can’t change genes, but you can note that serotonin-linked rigid behavior may have a biological root.
When you see a client who barely responds to SSRIs or social-skills training, remember that receptor differences might be in play.
Share the finding with families to underline that biology is not blame—it simply helps us tailor dose, timing, or combined therapy.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Track the time-of-day pattern of rigid or repetitive behavior—if it worsens when serotonin is naturally lowest, share the log with the prescribing doctor.
02At a glance
03Original abstract
The serotonin 2A receptor gene (HTR2A) harbors two functional single nucleotide polymorphisms (SNPs) that are frequent in populations of African and European descent; rs6311, which affects mRNA expression, and rs6314, which changes the amino acid sequence of the encoded protein and affects the signaling properties of the receptor. Multiple clinical associations support a role for these SNPs in cognitive and neuropsychiatric phenotypes, although studies in autism spectrum disorder (ASD) remain equivocal. Here, we tested transmission disequilibrium of rs6311 and rs6314 in a cohort of 158 ASD trios (simplex and multiplex), observing significant under-transmission of the minor "A" allele of rs6311 to offspring with ASD (permuted P = 0.0004). Consistent with our previous findings in the dorsolateral prefrontal cortex of unaffected individuals, rs6311/A decreases expression of HTR2A mRNA with an extended 5' untranslated region (UTR) in the frontopolar cortex in brain samples from 54 ASD patients and controls. Interpreting the clinical results in the context of our mRNA expression analysis, we speculate that any risk associated with rs6311 is conferred by greater expression of the long 5'UTR mRNA isoform. The current study corroborates earlier associations between rs6311 and ASD in a family study, supporting the hypothesis that rs6311 plays a modulatory role in ASD risk.
Autism research : official journal of the International Society for Autism Research, 2014 · doi:10.1002/aur.1383