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Dopamine D4 receptor gene polymorphism is associated with attention deficit hyperactivity disorder
G J LaHoste1, J M Swanson, S B Wigal
1Department of Physical Medicine and Rehabilitation, University of California, Irvine 92717-4550, USA.
Molecular Psychiatry
|May 1, 1996
Summary
The dopamine D4 receptor gene (DRD4) 7-repeat form is more common in children with attention deficit hyperactivity disorder (ADHD). This genetic variation may contribute to ADHD symptoms by affecting dopamine signaling.
Area of Science:
- Neuroscience
- Genetics
- Child Psychology
Background:
- Attention deficit hyperactivity disorder (ADHD) affects 3-6% of school-age children and has a familial component.
- Dopamine is implicated in ADHD, with the dopamine D4 receptor (DRD4) gene showing significant variability.
- The DRD4 gene is associated with Novelty Seeking behavior.
Purpose of the Study:
- To investigate the association between DRD4 gene variability and ADHD in children.
- To determine if specific DRD4 repeat forms are more prevalent in children diagnosed with ADHD.
Main Methods:
- Examined the length variability of a 48-bp repeat sequence within the DRD4 gene.
- Compared DRD4 repeat forms in children with ADHD and ethnically matched controls.
Main Results:
- Children with ADHD showed a significantly higher frequency of the 7-repeat DRD4 form compared to controls.
- The 7-repeat DRD4 form is known to result in a blunted intracellular response to dopamine.
Conclusions:
- Polymorphic variation in the DRD4 gene may be a contributing factor to ADHD symptom expression.
- While ADHD is multifactorial and polygenetic, DRD4 gene variants represent a potential genetic influence.