LACK OF AN ASSOCIATION BETWEEN A DOPAMINE-4 RECEPTOR POLYMORPHISM ANDATTENTION-DEFICIT HYPERACTIVITY DISORDER - GENETIC AND BRAIN MORPHOMETRIC ANALYSES/

Although the etiology of attention-deficit/hyperactivity disorder (ADH D) is likely multifactorial, family,(1) adoption,(2) and twin studies( 3) suggest that genetic factors contribute significantly. Polymorphism s of the dopamine 4 receptor (DRD4) affect receptor binding,4 and one allele with seven tandem repeats in exon 3 (DRD47R) has been associat ed with ADHD.(5,6) We examined this putative association in 41 childre n with severe ADHD and 56 healthy controls who were group matched for ethnicity and sex. The frequency of the DRD47R allele did not vary by diagnosis (0.220 vs 0.205 in patients and controls, respectively). Be havioral and brain anatomic MRI measures, previously found to discrimi nate patients from controls,(7) did not differ significantly between s ubjects having and those lacking a DRD47R allele. These data do not s upport the reported association between DRD47R and the behavioral or brain morphometric phenotype associated with ADHD.