Anemia associated with lead poisoning can be normocytic or microcytic; it is attributable to several mechanisms including (1) impaired heme synthesis (interference with two of the enzymes involved in heme synthesis: delta-aminolevulinic acid dehydratase and ferrochelatase), (2) shortened survival of red blood cells (hemolysis due to increased osmotic fragility and changes of the red blood cell shape) and (3) impaired renal production of erythropoietin [38]. This evidence concerns the gene EPO and anemia (phenotype).