6. If the patient has been receiving chronic transfusion therapy for greater than or equal to 1 year and has clinical evidence of iron overload by serum ferritin (mean of 3 ferritin levels >1000 and chronic transfusions >20 in a lifetime or MRI), evaluation by liver biopsy is required. Histological examination of the liver must document the absence of cirrhosis, bridging fibrosis and active hepatitis. The absence of bridging fibrosis will be determined using the histological grading and staging scale as described by Ishak and colleagues (1995).