Rare Genetic Variants Substantially Increase ADHD Risk, Study Finds
A new study published in nature has identified rare genetic variants that substantially elevate the risk of Attention Deficit Hyperactivity Disorder (ADHD), offering new insights into the biological underpinnings of the condition and potential avenues for earlier diagnosis and personalized intervention. The research, involving the analysis of over 62,000 individuals, reveals that uncommon genetic alterations can have a significant impact on brain progress and cognitive function in those with ADHD.
Understanding the Genetic Basis of ADHD
ADHD is a neurodevelopmental disorder affecting approximately 5% of children and 2.5% of adults [https://www.cdc.gov/ncbddd/adhd/data.html]. While previous research has linked common genetic variations to ADHD, the role of rarer genetic changes remained less clear. This study employed exome sequencing – a technique that focuses on the protein-coding regions of genes – to investigate the contribution of these rare variants.
Key Genes Identified and Their Impact on Brain Function
Researchers analyzed data from 8,895 individuals with ADHD and 53,780 control subjects. They pinpointed three genes – MAP1A,ANO8,and ANK2 – as having a strong association with ADHD risk,with statistical significance (P < 3.07 × 10−6) and increased odds ratios ranging from 5.55 to 15.13. This means individuals carrying rare variants in these genes had a significantly higher likelihood of being diagnosed with ADHD.
Further analysis revealed that these genes are involved in crucial brain functions:
* Synapse Function: The protein interaction networks associated with these genes are enriched for those involved in the communication between neurons. Disruptions in synaptic function are strongly implicated in neurodevelopmental disorders.
* RNA Processing: Proper RNA processing is essential for gene expression and brain development. Variants affecting this process can disrupt normal brain maturation.
* Cytoskeleton Association: The cytoskeleton provides structural support to neurons and is vital for their growth and connectivity.
The study also found that carrying rare deleterious variants was associated with a 2.25 IQ point decrease in a sample of 962 adults with ADHD. Individuals with both ADHD and intellectual disability exhibited a higher overall load of these genetic variants.
Connection to Other Neurodevelopmental Disorders
Interestingly, nine of the top 20 genes associated with ADHD in this study have also been linked to autism spectrum disorder (ASD) and other neurodevelopmental conditions. This overlap suggests shared genetic pathways contributing to these disorders. Moreover, the identified genes showed high levels of expression during both prenatal and postnatal brain development, highlighting the critical role of early brain development in ADHD etiology.
Additive Effect of Rare and Common Variants
The research confirmed that both rare and common genetic variants contribute to ADHD risk in an additive manner. This supports a polygenic model, meaning that multiple genes, each with a small effect, combine to influence an individual’s susceptibility to the disorder.
Implications for Diagnosis and Treatment
These findings have significant implications for clinical practice and future research:
* Refined Diagnostics: Assessing rare genetic variants could perhaps refine diagnostic pathways for ADHD, leading to more accurate diagnoses.
* Early Intervention: Identifying individuals at higher genetic risk could allow for earlier intervention planning and tailored educational support.
* Personalized Approaches: A deeper understanding of the specific genetic profiles of individuals with ADHD could pave the way for more personalized treatment strategies.
Future Research Directions
Future research will focus on identifying additional genes involved in ADHD and clarifying how specific variant patterns influence clinical outcomes. This will contribute to the development of more targeted and effective interventions for individuals with this complex neurodevelopmental disorder.
Reference:
Demontis D et al. Rare genetic variants confer a high risk of ADHD and implicate neuronal biology. Nature. 2025;DOI:10.1038/s41586-025-09702-8.
Key Takeaways:
* Rare genetic variants play a significant role in ADHD risk, ofen with a larger impact than common variants.
* The identified genes (MAP1A, ANO8, ANK2) are involved in critical brain functions like synapse formation, RNA processing, and cytoskeleton organization.
* There is a genetic overlap between ADHD and other neurodevelopmental disorders like autism.
* Genetic profiling may one day support earlier diagnosis and personalized treatment approaches for ADHD.