MAT1A and major depressive disorder: Consistent with the pathway analysis, we found a significant negative association between depression and adenosylhomocysteine nucleosidase (EC 3.2.2.9), S-ribosylhomocysteine lyase (EC 4.4.1.21), and S-adenosylmethionine synthetase (EC 2.5.1.6) (FDR q 0.004, 0.006, and 0.004, respectively) (Fig. 3C).