iron-overload-associated myopathy in patients on maintenance haemodialysis: a histocompatibility-linked disorder.

Unexplained proximal muscle weakness developed in 10 patients on chronic maintenance haemodialysis. Proximal muscle biopsy in 7 patients disclosed iron deposition in muscle fibres and/or macrophages. All 10 patients had severe iron overload (serum-ferritin level > 1000 ng/ml). Since HLA-A3, B7, and B14 antigens are associated with idiopathic haemochromatosis and, therefore, are linked with alleles regulating iron metabolism, HLA type was reviewed in 61 haemodialysis patients, including the 10 myopathic patients. Serum-ferritin levels showed a significant correlation (p<0.001) with the presence of the HLA-antigens. Close relatives of these patients with HLA-antigen-associated iron-overload myopathy did not have raised serum-ferritin levels. Patients on maintenance haemodialysis who have inherited the "haemochromatosis alleles" thus have an increased risk of iron overload and muscle iron deposition.