Deficiency of glutaredoxin 5 (GLRX5), a scaffold protein required for mitochondrial Fe-S cluster synthesis, activated IRP1, which inhibited ALAS2 translation and subsequently led to anemia in zebrafish, suggesting a role of IRP1 in coordinating Fe-S cluster and heme synthesis (Wingert et al., 2005). The gene discussed is GLRX5; the disease is anemia.