Table 1.

Characteristics of Hereditary Hemochromatosis.

	Gene	Mutation	Inheritance	Hepcidin levels	Pathophysiology
Type I	HFE	C282Y (6p21), H63D	AR	Low	Increased iron absorption
Type II –Juvenile hemochromatosis	HJV; hepcidin	1q21; 19q13	AR	Low	Increased iron absorption
Type III	TFR2	7q22	AR	Low	Increased iron absorption
Type IV*	FPN1	2q32	AD	High	Increased iron absorption

*Mutation results in 2 similar forms of disease: either a hemochromatosis-like illness with increased iron in hepatocytes due to hepcidin resistance (gain-of-function mutation) or reduced macrophage iron export with normal transferrin saturation called “classic ferroportin disease” (loss-of-function mutation).