Genetic Testing Could Be Helpful in Pediatric ADHD

New data presented at the American Professional Society of ADHD and Related Disorders (APSARD) 2026 Annual Conference challenge the long-standing view of attention-deficit/hyperactivity disorder (ADHD) as an exclusively polygenic condition and suggest that a meaningful subset of children with ADHD may benefit from clinical genetic testing.

Ryan Doan, PhD, FACMG, principal investigator of the Doan Lab, Harvard University, and assistant professor of pediatrics in the division of Genetics and Genomics at Boston Children’s Hospital, presented findings from an ongoing study examining the genetic architecture of pediatric ADHD in families recruited through the hospital’s Developmental Medicine Center. The cohort focused on children with early-onset ADHD who did not have autism, a population often excluded from genetic testing pathways.¹

“One of the questions we've been trying to address is what is how are these disorders different from one another?” Doan told Psychiatric Times.

“Many people have thought that ADHD is entirely polygenic,” he said. “In that case, on the clinical side, most kids with ADHD don’t get genetic testing such as exome or genome sequencing.”

However, when the research team applied exome and genome sequencing to this cohort, the results were striking. “We see about maybe 20% of our kids actually have an identifiable genetic diagnosis that can account for their ADHD presentation,” Doan reported, calling the finding “quite surprising.” He noted that this diagnostic yield is comparable to rates observed in autism.

In an additional 30% of families without a clearly pathogenic variant, the investigators identified strong candidate missense variants, often in genes already associated with autism or intellectual disability. According to Doan, these findings point to a broader phenotypic spectrum. “The same genes that cause autism are causing intellectual disability as well as now ADHD, but there are different types of variants,” he said.

One notable pattern was the enrichment of variants in chromatin methylation–related genes—pathways well established in autism research but not traditionally emphasized in ADHD. Functional studies suggest that missense variants behave differently from loss-of-function variants, both molecularly and clinically. “Our missense variants are very different from loss of function variants, both molecularly and phenotypically in the family,” Doan said.

These findings have potential implications for clinical practice. Current American College of Medical Genetics and Genomics² guidelines recommend exome-first testing for children with autism, but ADHD has not been included in similar recommendations. Doan argued that may need to change. “I think we’re pretty much should be there now for ADHD,” he said, adding that even children with ADHD without autism or other comorbidities should be considered for testing.

While many families will still receive negative results, Doan emphasized the value of actionable answers. “I think 10% to 20% of those kids are going to get an answer,” he said. “And I think that’s a substantial benefit to those families.”

Reference

1. Zimon M, Doan R, Arnett A. Family-based genomic analysis identifies clinically relevant rare variants in pediatric ADHD. Poster presented at the APSARD 2026 Annual Conference; January 15-18, 2026; San Diego, CA.

2. Richards S, Aziz N, Bale S, et al. Standards and guidelines for the interpretation of sequence variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Genet Med. 2015 May;17(5):405-424.