The A1 Allele at the D2 Dopamine Receptor Gene and Alcoholism:  A Reappraisal

Joel Gelernter, MD; David Goldman, MD; Neil Risch, PhD
JAMA. 1993;269(13):1673-1677. doi:10.1001/jama.1993.03500130087038.
Text Size: A A A
Published online

Objective.  —An allelic association between the Taq I "A" system A1 allele at the D2 dopamine receptor locus (DRD2) and either alcoholism or severe alcoholism has been proposed. Our purpose was to evaluate whether, based on all of the accumulated evidence, this association could be considered to be proven.

Data Sources.  —We considered data from all published reports of DRD2 allele frequency in alcoholics, controls, or both.

Study Selection.  —We concentrated on the issue of replication. We therefore considered all data reported (on white samples, because DRD2 allele frequency varies by race and ethnicity) since the first report by Blum et al in 1990.

Data Synthesis.  —We analyzed the set of data for differences in allele frequencies between alcoholics and controls, and for heterogeneity among samples. We also investigated the influence of the data from the first group to report an association (including a subsequent report from that group) on the findings. Our analysis shows that, when all studies subsequent to the original study are considered, there is no significant difference in DRD2 A1 allele frequency between alcoholics and controls, there is significant heterogeneity among reported alcoholics and reported controls, and there is no significant difference in DRD2 A1 allele frequency between severe and not severe alcoholics. Also, the two reports of Blum et al account for all of the (nonsignificant) differences seen between controls, alcoholics, and severe alcoholics.

Conclusions.  —In general, heterogeneity among studies (for alcoholics or controls) is considerably greater than differences between alcoholics and controls overall. The findings to date can best be explained by more conservative interpretations than a confirmed physiologically important allelic association between DRD2 alleles and alcoholism. These other possibilities include sampling error and ethnic variation in those studies that individually showed a large effect.(JAMA. 1993;269:1673-1677)


Sign In to Access Full Content

Don't have Access?

Register and get free email Table of Contents alerts, saved searches, PowerPoint downloads, CME quizzes, and more

Subscribe for full-text access to content from 1998 forward and a host of useful features

Activate your current subscription (AMA members and current subscribers)

Purchase Online Access to this article for 24 hours




Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).


Some tools below are only available to our subscribers or users with an online account.

Sign In to Access Full Content

Related Content

Customize your page view by dragging & repositioning the boxes below.