Manganese is a cofactor of numerous enzymes directly or indirectly involved in the processes of erythropoiesis (porphobilinogen synthase, arginase, and carboxylase or glycosylases) (29), therefore a deficiency of this element in the diet could lead to a significant limitation of the synthesis of functional, catalytically active forms of these enzymes, as a result resulting in the occurrence of anemia symptoms. The gene discussed is ALAD; the disease is anemia.