A haplotype relative risk study of the dopamine D4 receptor (DRD4) exon III repeat polymorphism and attention deficit hyperactivity disorder (ADHD).
Attention deficit hyperactivity disorder (ADHD) is a developmental syndrome expressed along three domains: inattention, hyperactive-impulsive, and combined type. Several investigations have recently examined the role of the dopamine DRD4 exon III repeat polymorphism in ADHD. The long 7 repeat allele of this receptor was shown in three family-based studies, but not in one case control design, to be a risk factor for this disorder. We now report an additional family-based study of DRD4 exon III repeat region and ADHD. However, in the current study we fail to observe preferential transmission of the DRD4 exon III long 7 repeat allele, chi(2) = 0. 142, P < 0.1, df = 1. Nor was any preferential transmission observed when genotypes were compared, chi(2) = 0.180, P > 0.1, df = 1. Possible reasons are discussed, especially lack of sufficient power in analying more refined phenotypes, why the current results in contrast to previous findings fail to support a role for the long form of the DRD4 receptor as a putative risk factor for ADHD.
Eisenberg
J
J
Child Psychiatry Clinic, S. Herzog Memorial Hospital, Jerusalem, Israel.
Zohar
A
A
Mei-Tal
G
G
Steinberg
A
A
Tartakovsky
E
E
Gritsenko
I
I
Nemanov
L
L
Ebstein
R P
RP
D000483:Alleles; D001289:Attention Deficit Disorder with Hyperactivity / Q000235:genetics*; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D002648:Child; D005091:Exons; D006239:Haplotypes; D006801:Humans; D011110:Polymorphism, Genetic; D017448:Receptors, Dopamine D2 / Q000235:genetics*; D050638:Receptors, Dopamine D4; D012306:Risk; D012307:Risk Factors; D020080:Tandem Repeat Sequences
C493599:DRD4 protein, human; D017448:Receptors, Dopamine D2; D050638:Receptors, Dopamine D4