METTL3 and major depressive disorder: Another study, analyzing 23 SNPs mapping inside five genes involved in the RNA modification (ALKBH5, METTL3, METTL14, WTAP and FTO), showed that in the Han population of China, the ALKBH5 gene was associated with MDD; furthermore, many SNPs inside the genes encoding the m6A system were associated with clinical symptoms of MDD such as anxiety, retardation and cognitive disturbance of MDD [88].