The effect of iron overload on red blood cell morphology

Abstract

A 76-year-old man with an extremely high serum ferritin concentration (33 790 μg/L) was referred to the National Reference Laboratory for further laboratory testing to determine the cause. Genetic analysis showed that he was a carrier of a haemo chromatosis-associated allele (H63D/hetero zygous). Pathology con fi rmed renal insuffi ciency and liver damage, with an exceptionally high bilirubin concen tration of 730 μmol/L and an unconjugated bilirubin concentration of 272 μmol/L. This light micro scopy smear showed that most of the red blood cells have a changed morphology (fi gure). Scanning electron micro scopy, by which high magnifi cations of the red blood cells can be viewed, showed that the cells form pointed extensions with large membrane pores (fi gure). This abnormality is not seen in red blood cells from healthy individuals (fi gure). We suggest that the presence of the H63D haemochromatosisassociated allele is partly the cause of the exceptionally high serum ferritin concentrations, which brings about the abnormal red blood cell morphology.