Early erroneous diagnosis of rheumatic disease is common in subjects with arthropathy due to hereditary hemochromatosis. A 71-year-old male with chronic obstructive pulmonary disease and monoclonal gammopathy underwent hip replacement and was referred to our Department because of altered liver function tests. Test results were negative for hepatitis B surface antigen and hepatitis C virus, and positive for rheumatoid factor. A diagnosis of rheumatoid arthritis had been made on the basis of compatible joint involvement and laboratory data and steroid treatment prescribed. Since his serum ferritin was 3249 ng/mL, genetic testing for hereditary hemochromatosis was carried out and revealed homozygosity for Cys282Tyr mutation in the HFE gene. Li...