KLF11 and major depressive disorder: Follow-up tests revealed significantly decreased methylation in PD patients with comorbid MDD (PD + MDD; N = 27) regarding average KLF11 methylation (p = 0.008) and CpG site 3 methylation (p = 0.006) compared to PD patients without comorbid MDD as well as compared to healthy controls, again regarding average methylation (p = 0.010) and methylation at CpG site 3 (p = 0.006) (see Table 2, Fig. 1).