Determination of end organ function The effect of iron overload will be studied in three principal areas: liver, heart and endocrine organs. All measurements will be performed at baseline and at 6 and 12 months following the start of the series of 12 phlebotomies. Hepatic function will be determined by measurement of liver enzymes (alkaline phosphatase, aspartate aminotransferase and alanine aminotransferase) and liver function testing including total bilirubin, albumin and INR. Cardiac function will be determined by magnetic resonance imaging and serum brain natriuretic peptide and troponin. Endocrine function will be determined by measurement of serum LH, FSH, TSH, free T4, testosterone (males) and fasting glucose.