Catechol-O-methyltransferase Val158Met polymorphism and hyperactivity symptoms in Egyptian children with autism spectrum disorder.
Among Egyptian children with ASD, those carrying the COMT Val/Val genotype show the sharpest hyperactivity and autism severity.
01Research in Context
What this study did
Researchers looked at one gene in Egyptian kids with autism. The gene makes an enzyme that breaks down dopamine. They wanted to know if different versions of this gene linked to hyperactivity.
They used two checklists: the Conners for ADHD signs and the CARS for autism severity. Then they compared scores across the three gene types.
What they found
Kids with the Val/Val genotype had the highest hyperactivity scores. They also scored highest on autism severity. Yet the gene types showed up equally often in kids with and without autism.
In short, the gene did not predict who had autism, but it did predict how intense the symptoms were inside the autism group.
How this fits with other research
Casey et al. (2009) saw the same trend earlier: COMT variants and ADHD traits in autistic kids. Their link was weaker, so the new study firms up the signal.
Roohi et al. (2009) found a parallel story with a different dopamine gene, MAO-A. Both papers say, 'Dopamine genes matter when autism and ADHD overlap.'
Tonizzi et al. (2022) meta-analysis shows kids who carry both labels have worse executive control. The gene finding helps explain why the overlap hurts more.
Why it matters
You cannot change genes, but you can plan smarter. When an autistic client shows big hyperactivity, think 'possible Val/Val COMT.' Expect longer response times to stimulant meds or more self-stim when dopamine dips. Build extra movement breaks and reward dense trials into the plan.
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02At a glance
03Original abstract
Catechol-O-methyltransferase (COMT) plays an important role in the catabolism of brain dopamine and norepinephrine, which have been implicated in the pathogenesis of Autism spectrum disorder (ASD) as well as in other neuropsychatric disorders. We aimed to investigate the association of COMT Val158Met gene polymorphism with ASD and to examine the influence of such genotypes on hyperactivity symptoms in ASD patients. Eighty ASD patients (mean age 9 ± 1.9 years) and 100 control children (mean age 8.9 ± 1.9 years) were examined. COMT Val58Met polymorphism was genotyped using Tetra-primer ARMS-PCR method. The clinical diagnosis of ASD and ADHD were confirmed according to the DSM-IV criteria for research. We found no significant difference in genotypes or alleles' frequencies of COMT Val158Met polymorphism between ASD patients and control group. There was a significant association between COMT (Val/Val) genotype and both increasing CARS (p=0.001) and hyperactivity scores (p=0.006). Regarding Conner's Score, the DSM-IV hyperactive impulsive were significantly higher in Val/Val genotype than both Met/Val and Met/Met genotypes (p=0.03). Our data suggested an association between COMT Val58Met polymorphism and hyperactivity symptoms in Egyptian children with ASD.
Research in developmental disabilities, 2013 · doi:10.1016/j.ridd.2013.04.002