Dopamine DRD4 receptor polymorphism and attention deficit hyperactivity disorder.
A polymorphism in the dopamine receptor 4 gene (DRD4) has been related to novelty seeking, Tourette's syndrome, and attention deficit hyperactivity disorder (ADHD). The variability is in a 48-bp repeat in exon 3 of the gene (a transmembrane region). This study examined the relation of the 7-repeat (i.e., high-risk) allele to questionnaire-based diagnoses of ADHD (both combined type and inattentive type). Several positive findings were obtained for ADHD-inattentive type. In an association test, the 7-repeat allele occurred more frequently in children with ADHD-inattentive type than in control children. In genetically discordant sibling pairs, the sibling with a greater number of 7-repeat alleles displayed more inattentive symptoms than his/her co-sibling with fewer 7-repeat alleles. For ADHD-combined type, the 7-repeat allele frequency was greater than that in the control sample. However, a quantitative transmission disequilibrium test yielded no significant linkage of the 7-repeat allele with hyperactive-impulsive symptoms. A categorical TDT yielded no significant findings, but the number of transmissions was small, especially for ADHD-inattentive type.
Interdisciplinary Graduate Committee on Genetics, University of Arizona, USA. dcr091@ag.arizona.edu
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DC
Rowe
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Stever
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Giedinghagen
J M
JM
Gard
H H
HH
Cleveland
S T
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Terris
J H
JH
Mohr
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Sherman
A
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Abramowitz
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Waldman
D000293:Adolescent; D000483:Alleles; D001130:Arizona; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000235:genetics*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005006:Ethnicity; D005091:Exons; D005838:Genotype; D005845:Georgia; D006801:Humans; D007407:Interviews as Topic; D011110:Polymorphism, Genetic; D017448:Receptors, Dopamine D2 / Q000235:genetics*; D050638:Receptors, Dopamine D4; D012091:Repetitive Sequences, Nucleic Acid; D011795:Surveys and Questionnaires
C493599:DRD4 protein, human; D017448:Receptors, Dopamine D2; D050638:Receptors, Dopamine D4