Monoamine Oxidase A (MAOA) is a critical enzyme in the catabolism of 
monoaminergic neurotransmitters. MAOA transcriptional activity is thought to be 
regulated by a well characterized 30 base pair (bp) variable nucleotide repeat 
(VNTR) that lies approximately ∼1000 bp upstream of the transcriptional start 
site (TSS). However, clinical associations between this VNTR genotype and 
behavioral states have been inconsistent. Herein, we describe a second, 10 bp 
VNTR that lies ∼1500 bp upstream of the TSS. We provide in vitro and in silico 
evidence that this new VNTR region may be more influential in regulating MAOA 
transcription than the more proximal VNTR and that methylation of this CpG-rich 
VNTR is genotype dependent in females. Finally, we demonstrate that genotype at 
this new VNTR interacts significantly with history of child abuse to predict 
antisocial personality disorder (ASPD) in women and accounts for variance in 
addition to that explained by the prior VNTR.