We found that the combination of the absence of GSTM1 gene with the of the GSTM1 gene with the polymorphism GSTA1*B/*B, and the presence of the GSTT1 gene, represents a risk factor for schizophrenia, indicating that the combination of different GST polymorphisms has a role in the predisposition to schizophrenia, probably affecting the capacity of the cell to detoxify the oxidized metabolites of catecholamines.
We isolated genomic DNA from peripheral blood of 93 individuals with SCZ and 99 healthy control subjects' genotypes analyzing them for GSTM1, GSTT1 and GSTP1 using polymerase chain reaction.
Furthermore, among the few relatively common CNVs observed in patients and controls, the combined analysis of gene copy number genotypes at two glutathione S-transferase (GST) genes, GSTM1 (glutathione S-transferase mu 1) (1p13.3) and GSTT2 (glutathione S-transferase theta 2) (22q11.23), showed a statistically significant association of non-null genotypes at both loci with an additive effect for increased vulnerability to schizophrenia (odds ratio of 1.92; P=0.0008).