PPFIA4 and major depressive disorder: Thus far, only 4 pilot studies have investigated genome-wide DNA methylation patterns for their potential as predictors of response to pharmacological antidepressant treatment: Takeuchi et al. (2017) identified significantly altered methylation at 2 CpGs in the genes coding for Liprin-Alpha-4 (PPFIA4) and Sulfate-Glucosamine 3-Sulfotransferase 1 (HS3ST1) to be related to response to 6-week paroxetine treatment in 10 responders compared with 10 nonresponders in a sample of Japanese patients with MDD.