Association of a monoamine oxidase-a gene promoter polymorphism with ADHD and anxiety in boys with autism spectrum disorder.

Roohi et al. (2009) looked at DNA from boys with autism. They checked which version of the MAO-A gene each boy carried. Then they asked parents and teachers to rate the boys' ADHD and anxiety symptoms.

Boys with the 4-repeat form of the MAO-A gene had higher parent-rated ADHD scores. Teachers also rated these boys as more anxious than boys with the 3-repeat form. The difference was statistically significant.

Berkovits et al. (2014) later found similar small links between dopamine genes and ADHD in kids with ASD. They added emotion dysregulation to the picture, building on the MAO-A finding.

Fahmie et al. (2013) conceptually replicated this approach in Egyptian boys. They linked the COMT Val/Val genotype to hyperactivity in ASD, showing the pattern holds across ethnic groups.

Casey et al. (2009) used the same gene-ASD design in the same year. They tested COMT and BDNF genes instead of MAO-A, finding only weak associations with ADHD and anxiety.

When you see severe ADHD or anxiety in a boy with ASD, remember that genes may play a role. The 4-repeat MAO-A allele won't change your treatment plan, but it helps explain why some kids struggle more. Consider this context when explaining symptom severity to families or when selecting intervention intensity.