Test of association between TaqIA A1 allele and alcohol use disorder phenotypes in a sample of adolescent patients with serious substance and behavioral problems.
Several studies have demonstrated a significant association between the A1 allele of the TaqIA polymorphism and various phenotypes of alcoholism, others have not, and two studies have shown the reversed association, where the A2 allele was associated with higher levels of alcohol consumption. We sought to test for an association between early onset (in childhood or adolescence) alcohol use disorders and the DRD2 TaqIA polymorphism and to resolve some of the hypothesized explanations for previous negative results, utilizing a larger sample than many previous studies.


METHODS
We selected individuals with a lifetime alcohol abuse or dependence (n=239) diagnosis from a clinically ascertained sample of youth (ages 13-19) with serious conduct and substance problems (about 90% also met criteria for conduct disorder and a cannabis use disorder) and compared them with individuals without a lifetime alcohol use disorder diagnosis ascertained from (1) community adolescent controls (n=151), (2) siblings of patients (n=87) and (3) other adolescent patients (n=92). Cases were compared with each control group, separately, by genotype using the chi(2)-test. Using 78 adolescent patients with an alcohol use disorder where genotypic information was available for both parents, we conducted the transmission disequilibrium test (TDT).


RESULTS
Case-control results were non-significant using the entire community control sample (chi(2)(2)=1.92; p=0.38) and when restricting the sample to Caucasians (chi(2)(2)=3.81; p=0.15) or Hispanics (chi(2)(2)=1.70; p=0.43). Case-control results using the other comparison groups and TDT results were also non-significant.


CONCLUSIONS
We did not find support for an association between the TaqIA polymorphism and early onset alcohol use disorders.
Sakai
Joseph T
JT
Department of Psychiatry, Division of Substance Dependence, University of Colorado School of Medicine, Denver, CO 80262, USA. joseph.sakai@uchsc.edu
Hopfer
Christian J
CJ
Hartman
Christie
C
Haberstick
Brett C
BC
Smolen
Andrew
A
Corley
Robin P
RP
Stallings
Michael C
MC
Young
Susan E
SE
Timberlake
David
D
Hewitt
John K
JK
Crowley
Thomas J
TJ
D000293:Adolescent; D000328:Adult; D000437:Alcoholism / Q000235:genetics*; D016022:Case-Control Studies; D002648:Child; D005260:Female; D005838:Genotype; D006801:Humans; D015810:Linkage Disequilibrium; D008297:Male; D002189:Marijuana Abuse / Q000235:genetics; D001523:Mental Disorders / Q000235:genetics*; D010641:Phenotype; D017448:Receptors, Dopamine D2 / Q000235:genetics*; D012016:Reference Values; D035781:Siblings; D012907:Smoking / Q000235:genetics; D019966:Substance-Related Disorders / Q000235:genetics*; D019914:Taq Polymerase
D017448:Receptors, Dopamine D2; D019914:Taq Polymerase