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The genetics of attention deficit hyperactivity disorder
Anita Thapar1, Michael O'Donovan, Michael J Owen
1Department of Psychological Medicine, Cardiff University, School of Medicine, Heath Park, Cardiff CF14 4XN, UK thapar@cardiff.ac.uk
Human Molecular Genetics
|October 26, 2005
Summary
Genetic research in attention deficit hyperactivity disorder (ADHD) implicates dopamine pathways. Meta-analyses confirm associations between ADHD and specific gene polymorphisms, including DRD4 and SLC6A3.
Area of Science:
- Neuroscience
- Genetics
- Psychiatry
Background:
- Attention deficit hyperactivity disorder (ADHD) is a common, heritable childhood disorder with unclear causes.
- Genetic factors are significant, but specific chromosomal regions remain unidentified.
- Neuroimaging and pharmacological studies suggest neurotransmitter system involvement, particularly dopaminergic pathways.
Purpose of the Study:
- To investigate the genetic underpinnings of ADHD.
- To explore associations between specific gene polymorphisms and ADHD.
- To identify potential etiological factors contributing to ADHD.
Main Methods:
- Genome-wide linkage studies were limited.
- Candidate gene association studies were employed.
- Meta-analyses and pooled data analyses were conducted on existing genetic data.
Main Results:
- Meta-analyses support associations between ADHD and polymorphisms in DRD4, DRD5, and SLC6A3 (dopamine receptors and transporter).
- Replicated evidence suggests associations with SNAP-25 and SLC6A4 (serotonin transporter).
- No single chromosomal region has been definitively linked to ADHD.
Conclusions:
- Dopaminergic pathways are strongly implicated in ADHD etiology.
- Specific gene polymorphisms are associated with ADHD, providing etiological clues.
- Future research will focus on gene-phenotype links and gene-environment interactions.