Association analysis of the GSK-3beta T-50C gene polymorphism with schizophrenia and bipolar disorder

Glycogen synthase kinase-3beta (GSK-3beta) has been implicated in the pathogenesis of major psychoses. In this paper, the T-50C polymorphism of the GSK-3beta gene has been studied in patients with schizophrenia (n=432), patients with bipolar disorder (n=416) and in a healthy control group (n=408). Consensus diagnosis by at least two psychiatrists was made for each patient, according to DSM-IV and ICD-10 criteria, using the Structured Clinical Interview for DSM-IV Axis I Disorders. Genotypes were established by the polymerase chain reaction-restriction fragment length polymorphism method. We have found a trend towards an association for the C allele in the whole group of schizophrenic patients (p=0.088) and for the heterozygous T/C genotype of bipolar patients (0.095). Significant differences of genotype distribution and allele frequencies of the T-50C polymorphism were found in the female group of bipolar II patients (p=0.015 for genotypes and p=0.009 for alleles). In conclusion, this polymorphism may be associated with female gender in bipolar II disorder.