In microarray analysis of the peripheral blood of 36 MDD patients and 20 healthy controls, we found that both RNA methyltransferases (METTL3, METTL14, and WTAP) and demethylases (FTO and ALKBH5) were significantly downregulated in the patient group (Fig. 1a). The gene discussed is ALKBH5; the disease is major depressive disorder.