Iron-saturated transferrin attaches to cell transferrin recep¬tors and excess iron gains entry into the cell (see Fig. 1). Although much of the iron is stored as hemosiderin, for example, within the Kuffer cells of the liver, and causes no damage to tissues, some free iron is released into paren-chymal cells. Free iron catalyzes the formation of reactive oxygen species and the hydroxyl radical causes damage to cells. With damage and destruction of cells there is by collagen and fibrous tissue that weakens the muscular wall of the heart. Severe damage and weak¬ness primarily to heart muscle is called cardiomyopathy. Less blood is ejected from the left ventricle and heart failure symptoms and signs occur. The weakened heart muscle is stretched and the heart becomes dilated, resulting in a dilated cardiomyopathy, but some restriction to filling of the heart occurs and there are also features of a restric¬tive cardiomyopathy (see the chapter Cardiomyopathy). Excessive iron is distributed throughout the myocardium and in the electrical conducting tissues and arrhythmias may occur.
B. Symptoms and Signs
The symptoms and signs of hemochromatosis depend on the organ or organs involved. It usually takes 20–30 years of excessive absorption before the disease manifests. In affected women time onset is usually delayed because of menstruation.

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