Several candidate gene association studies of ERN have been reported. Fallgatter et al. (2004), using a very small sample (n=27), found larger ERN amplitudes in the carriers of the low-activity short allele of the serotonin transporter gene (5-HTTLPR). Similar results were obtained in another study including a small group of children hat was very mixed with respect to psychiatric diagnoses and medication (Althaus et al., 2009). However, a subsequent study using a larger sample (n=89) and more detailed genotyping taking into account the A/G SNP in the long allele (Olvet et al., 2010), failed to replicate this finding. Another study found a highly significant effect of a functional polymorphism in the brain-derived neurotrophic factor (BDNF) gene on ERN amplitude and other characteristics, with Val/Val genotype associated with larger ERN response and stronger inter-trial phase locking (Beste et al., 2010).
