Aims: In this study we explored possible epistasis between CYP2D6 (*3, *4, *5, *6 and *1xN), CYP3A5 (*3), CYP1A2 (*1C and *1F) and ABCB1 (G2677T) in schizophrenia and related disorders.
Materials & methods: A total of 344 patients diagnosed with schizophrenia and related disorders, and 484 healthy controls participated in the present study. We analyzed gene-gene interactions by multifactor dimensionality reduction.
Results: A four-way model including ABCB1 G2677T, CYP3A5*3, CYP1A2*1F and CYP2D6*4 variants had the best overall performances (accuracy: 0.573) and a crossvalidation consistency of 10/10 (permutation testing p < 0.004).
Conclusion: Our results suggest a significant involvement of CYPs and transporters in brain metabolism and homeostasis, and provide evidence of gene-gene interactions among xenobiotic metabolizing and transporter genes in the context of schizophrenia.