MAOA and major depressive disorder: Monoamine oxidase‐A (MAOA) metabolises monoamines and as such it is implicated in the pathophysiology of stress‐related illnesses, including major depressive disorder, addiction and violent behaviour.1, 2 A major mediator of MAOA expression is a polymorphic repetitive domain termed the uVNTR (upstream variable number tandem repeat) located in what was considered the promoter of the major transcript of the MAOA gene.3 The uVNTR is a 30 base pair repeat element that can be present in 2, 3, 3.5, 4 or 5 copies.