Study of dopamine receptors genes polymorphisms in bipolar patients with comorbid alcohol abuse.
Alcoholism is present in approximately 40-60% of bipolar patients. This comorbidity between bipolar disorder and alcoholism is high and may result from existence of common genetic factors for the two disorders. In both disorders, dysregulation of the dopaminergic neurotransmission had been implicated. Association analyses revealed several candidate genes acting in the dopaminergic pathway and polymorphisms in those genes that might be associated with both disorders.


OBJECTIVE
The aim of this study was to analyse possible relationship between polymorphisms in the dopaminergic pathway genes (one SNP for each dopamine receptor gene 1-4) and alcohol abuse comorbidity in bipolar patients.


METHODS
We analysed 317 patients with bipolar disorder. In this group, 42 patients were diagnosed with alcohol abuse. The diagnosis was made for each patient by at least two psychiatrists, using structured clinical interviews for DSM-IV Axis I disorders (SCID). The control group consisted of 350 subjects. We performed RFLP analysis of polymorphisms in four genes: DRD1, DRD2, DRD3, and DRD4.


RESULTS
We have not found association of any of the analysed polymorphisms in the dopamine genes in the group of bipolar patients with comorbid alcohol abuse as compared to the control group. In the male group of bipolar patients with comorbid alcohol abuse, we also have not observed any significant differences between the patients and the control subjects.


CONCLUSIONS
Our findings suggest that the analysed polymorphisms of the dopamine genes polymorphisms may not be involved in the shared genetic vulnerability to both, bipolar disorder, and alcohol abuse.
Szczepankiewicz
Aleksandra
A
Laboratory of Psychiatric Genetics, Poznan University of Medical Sciences, Poznan, Poland. alszczep@amp.edu.pl
Dmitrzak-Weglarz
Monika
M
Skibínska
Maria
M
Słopień
Agnieszka
A
Leszczyńska-Rodziewicz
Anna
A
Czerski
Piotr
P
Hauser
Joanna
J
D000328:Adult; D000437:Alcoholism / Q000235:genetics*; D001714:Bipolar Disorder / Q000235:genetics*; D015897:Comorbidity; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D011954:Receptors, Dopamine / Q000235:genetics*; D012016:Reference Values
D011954:Receptors, Dopamine