The present results for the first time demonstrating KLF11 promoter hypomethylation—presumably leading to increased KLF11 gene expression (cf. Suzuki and Bird 2008) and, consequently, an overexpression of the MAOA gene (Grunewald et al. 2012)—in depression-related phenotypes are in line with a previous finding of increased KLF11 and MAOA levels in MDD patients compared to healthy controls (Harris et al. 2015) and with studies reporting MAOA hypomethylation in female patients with MDD (Melas et al. 2013; Melas and Forsell 2015). This evidence concerns the gene MAOA and major depressive disorder.