Monoamine oxidase-A polymorphisms might modify the association between the dopamine D2 receptor gene and alcohol dependence.
OBJECTIVE
Low monoamine oxidase (MAO) activity and the neurotransmitter dopamine are 2 important factors in the development of alcohol dependence. MAO is an important enzyme associated with the metabolism of biogenic amines. Therefore, the present study investigates whether the association between the dopamine D2 receptor (DRD2) gene and alcoholism is affected by different polymorphisms of the MAO type A (MAOA) gene.


METHODS
A total of 427 Han Chinese men in Taiwan (201 control subjects and 226 with alcoholism) were recruited for the study. Of the subjects with alcoholism, 108 had pure alcohol dependence (ALC) and 118 had both alcohol dependence and anxiety, depression or both (ANX/DEP ALC). All subjects were assessed with the Chinese Version of the Modified Schedule of Affective Disorders and Schizophrenia-Lifetime. Alcohol dependence, anxiety and major depressive disorders were diagnosed according to Diagnostic and Statistical Manual of Mental Disorders, fourth edition criteria.


CONCLUSIONS
The genetic variant of the DRD2 gene was only associated with the ANX/DEP ALC phenotype, and the genetic variant of the MAOA gene was associated with pure ALC. Subjects carrying the MAOA 3-repeat allele and genotype A1/A1 of the DRD2 were 3.48 times (95% confidence interval = 1.47-8.25) more likely to be ANX/DEP ALC than the subjects carrying the MAOA 3-repeat allele and DRD2 A2/A2 genotype. The MAOA gene may modify the association between the DRD2 gene and ANX/DEP ALC phenotype.
Huang
San-Yuan
SY
Department of Psychiatry, Tri-Service General Hospital, Taiwan, ROC.
Lin
Wei-Wen
WW
Wan
Fang-Jung
FJ
Chang
Ai-Ju
AJ
Ko
Huei-Chen
HC
Wang
Tso-Jen
TJ
Wu
Pei-Lin
PL
Lu
Ru-Band
RB
D000328:Adult; D000437:Alcoholism / Q000453:epidemiology / Q000235:genetics* / Q000378:metabolism*; D000483:Alleles; D001008:Anxiety Disorders / Q000175:diagnosis / Q000453:epidemiology; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D015870:Gene Expression / Q000235:genetics; D005838:Genotype; D006801:Humans; D008297:Male; D008995:Monoamine Oxidase / Q000235:genetics* / Q000378:metabolism*; D011110:Polymorphism, Genetic / Q000235:genetics*; D017448:Receptors, Dopamine D2 / Q000235:genetics*; D012720:Severity of Illness Index
D017448:Receptors, Dopamine D2; D008995:Monoamine Oxidase