Pharmacogenetic predictor of extrapyramidal symptoms induced by antipsychotics: Multilocus interaction in the mTOR pathway

Antipsychotic (AP) treatment-emergent extrapyramidal symptoms (EPS) are acute adverse reactions of APs. The aim of the present study is to analyze gene-gene interactions in nine genes related to the mTOR pathway, in order to develop genetic predictors of the appearance of EPS. 243 subjects (78 presenting EPS: 165 not) from three cohorts participated in the present study: Cohort 1, patients treated with risperidone, (n=114); Cohort 2, patients treated with APs other than risperidone (n=102); Cohort 3, AP-naïve patients with first-episode psychosis treated with risperidone, paliperidone or amisulpride, n=27. We analyzed gene-gene interactions by multifactor dimensionality reduction assay (MDR). In Cohort 1, we identified a four-way interaction, including the rs1130214 (AKT1), rs456998 (FCHSD1), rs7211818 (Raptor) and rs1053639 (DDIT4), that correctly predicted 97 of the 114 patients (85% accuracy). We validated the predictive power of the four-way interaction in Cohort 2 and in Cohort 3 with 86% and 88% accuracy respectively. We develop and validate a powerful pharmacogenetic predictor of AP-induced EPS. For the first time, the mTOR pathway has been related to EPS susceptibility and AP response. However, validation in larger and independent populations will be necessary for optimal generalization.