A Linkage Study Between the GABAA β2 and GABAAγ2 Subunit Genes and Major Psychoses

Background:Alterations of the γ-aminobutyric acid (GABA) system have been implicated in the pathophysiology of major psychoses.Objective:Restriction fragment length polymorphisms associated with the human γ-aminobutyric acid type A (GABAA) β2 and GABAA γ2 subunit genes on chromosome 5q32-q35 were tested to determine whether they confer susceptibility to major psychoses.Methods:Thirty-two schizophrenic families and 25 bipolar families were tested for linkage.Results:Nonparametric linkage (NPL) analysis performed by GENEHUNTER showed no significant NPL scores for both genes in schizophrenia (GABAAβ2: NPL narrow=−0.450; NPL broad=−0.808; GABAA γ2: NPL narrow=0.177; NPL broad=−0.051) or bipolar disorder (GABAA β2: NPL narrow=0.834; NPL broad=0.783; GABAA γ2: NPL narrow=−0.159; NPL broad=0.070).Conclusion:Linkage analysis does not support the hypothesis that variants within the GABAA β2 and GABAA γ2 genes are significantly linked to major psychoses in a Portuguese population.