GLRX5 and sideroblastic anemia: Consistent with the zebrafish studies, RNAi knockdown of GLRX5 in K562 cells markedly reduced ALAS2 expression, and deficiency of GLRX5 in a patient caused by an intronic mutation that caused missplicing significantly increased the IRE-binding activity of IRP1, and caused sideroblastic anemia (Camaschella et al., 2007; Ye et al., 2010).