ABSTRACT
The available data from preclinical and pharmacological studies on the role of gamma amino butyric acid (GABA) support the hypothesis that a dysfunction in brain GABAergic system activity contributes to the vulnerability to bipolar affective disorders (BPAD). Moreover, the localization of the alpha3 subunit GABA receptor GABRA3 gene on the Xq28, a region of interest in certain forms of bipolar illness, suggests that GABRA3 may be a candidate gene in BPAD. In the present study, we tested the genetic contribution of the GABRA3 dinucleotide polymorphism in a European multicentric case-control sample, matched for sex and ethnogeographical origin. Allele and genotype (in females) frequencies were compared in 185 BPAD patients and 370 controls. A significant increase of genotype 1-1 was observed in BPAD females compared to controls (P=0.0004). Furthermore, when considering recessivity of allele 1 (females with genotype 1-1 and males carrying allele 1), results were even more significant (P= 0.00002). Our findings suggest that the GABRA3 polymorphism may confer susceptibility to or may be in linkage disequilibrium with another gene involved in the genetic etiology of BPAD.
Subject(s)
Bipolar Disorder/genetics , Receptors, GABA/genetics , X Chromosome , Alleles , Case-Control Studies , Europe , Female , Gene Frequency , Genotype , Humans , Linkage Disequilibrium , Male , Polymorphism, GeneticABSTRACT
Available data on gamma amino butyric acid (GABA) support the hypothesis that a dysfunction in the brain GABAergic system activity contributes to vulnerability to affective disorders (AD), including bipolar disorder (BPAD) and unipolar disorder (UPAD). The localization of the alpha3 subunit GABA receptor (GABRA3) gene in Xq28, a region of interest for BPAD suggests that GABRA3 may be a relevant candidate gene. In the present study, we tested the genetic contribution of the GABRA3 dinucleotide polymorphism in a European multicentre UPAD case-control sample [UPAD (n = 106), controls (n = 212)]. Our negative results suggest that GABRA3 does not confer susceptibility nor is it in linkage disequilibrium with another close gene involved in the genetic aetiology of UPAD.
