Table 3. Hereditary iron overload disorders divided according to TSAT, anemia, pathophysiology, and iron distribution.

TSAT	Anemia (iron restricted erythropoiesis)	No anemia	Pathophysiological mechanisms	Cellular iron distribution
High/very high	Atransferrinemia, DMT1 deficiency	Hemochromatosis	Increased iron absorption and macrophage iron release	Parenchymal and diffuse; can be mixed in later and severe stages
		• Type 1
		• Type 2A, 2B
		• Type 3
		• Type 4 (formerly type 4B)
Low/normal	Aceruloplasminemia		Defective iron export from storage cells	Parenchymal and diffuse with brain iron overload
		Ferroportin disease (formerly hemochromatosis type 4A)		Reticulo-endothelial; can be mixed in later stages

TSAT, transferrin saturation.