Determinants of disease expression in Australian haemochromatosis patients.

Many of the clinical manifestations of haemochromatosis are determined by the hepatic iron concentration which, in turn, may be influenced by environmental and genetic factors. The environmental factors that influence iron stores include age, gender and blood loss (pathological and physiological). There is evidence that genetic factors also influence hepatic iron accumulation, as patients with two copies of the ancestral haplotype accumulate more iron than subjects with one or no copies of the ancestral haplotype. Concordance of iron storage between siblings also suggests genetic factors play an important role in determining disease expression. However, clarification of the exact role of genetic factors awaits the conduct of further studies following the cloning of the haemochromatosis gene.