Interaction effects of the 5-HTT and MAOA-uVNTR gene variants on pre-attentive EEG activity in response to threatening voices

Both the serotonin transporter polymorphism (5-HTTLPR) and the monoamine oxidase A gene (MAOA-uVNTR) are considered genetic contributors for anxiety-related symptomatology and aggressive behavior. Nevertheless; an interaction between these genes and the pre-attentive processing of threatening voices –a biological marker for anxiety-related conditions– has not been assessed yet. Among the entire sample of participants in the study with valid genotyping and electroencephalographic (EEG) data (N?=?140); here we show that men with low-activity MAOA-uVNTR; and who were not homozygous for the 5-HTTLPR short allele (s) (n?=?11); had significantly larger fearful MMN amplitudes –as driven by significant larger ERPs to fearful stimuli– than men with high-activity MAOA-uVNTR variants (n?=?20). This is in contrast with previous studies; where significantly reduced fearful MMN amplitudes; driven by increased ERPs to neutral stimuli; were observed in those homozygous for the 5-HTT s-allele. In conclusion; using genetic; neurophysiological; and behavioral measurements; this study illustrates how the intricate interaction between the 5-HTT and the MAOA-uVNTR variants have an impact on threat processing; and social cognition; in male individuals (n?=?62).