A linkage study between the GABAA beta2 and GABAA gamma2 subunit genes and major psychoses

Abstract

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 (GABAA β2: 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