 Patients without liver disease or diabetes had similar survival rate to the general population.Haemochromatosis is one of the most common heritable genetic conditions in people of Northern European extraction, with a prevalence of one in 200.The disease has a variable penetration, and about one in 10 people of this demographic carry a mutation in one of the genes regulating iron metabolism, the most common allele being the C282Y allele in the "HFE" gene.