The role of the measurement of hepatic iron in the diagnosis of genetic hemochromatosis was studied, with particular reference to the differentiation of early hemochromatosis from alcoholic siderosis and the critical hepatic iron concentration associated with fibrosis in hemochromatosis. Hepatic iron was measured in 30 homozygous relatives of 17 hemochromatosis probands, 8 heterozygous relatives, 51 patients with alcoholic liver disease and 40 control subjects. Hepatic iron concentrations were greatly increased in the majority of homozygous hemochromatosis subjects, and there was little overlap with the other groups. In the absence of alcoholism, fibrosis or cirrhosis in hemochromatosis was present only with hepatic iron concentrations above a threshold of approximately 400 mumoles per gm (22.3 mg per gm) dry weight. In some heterozygous hemochromatosis subjects and in some alcoholic patients, hepatic iron concentrations were in the range seen in young homozygous subjects. However, an age-related rise in hepatic iron was seen only in hemochromatosis homozygotes, and calculation of an hepatic iron index (hepatic iron/age) resulted in a clear distinction between homozygotes and the other three groups. It is concluded: that chemical measurement of hepatic iron concentration, when corrected for the age of the subject, reliably distinguishes early hemochromatosis from alcoholic siderosis, and, that there appears to be a threshold level of hepatic iron above which there is a high risk of fibrosis.

Background: Hemochromatosis in white subjects is mostly due to homozygosity for the common C282Y substitution in HFE. Although clinical symptoms are preventable by early detection of the genetic predisposition and prophylactic treatment, population screening is not currently advocated because of the discrepancy between the common mutation prevalence and apparently lower frequency of clinical disease. This study compared screening for hemochromatosis in subjects with or without a family history. Methods:We assessed disease expression by clinical evaluation and liver biopsy in 672 essentially asymptomatic C282Y homozygous subjects identified by either family screening or health checks. We also observed a subgroup of untreated homozygotes with normal serum ferritin levels for up to 24 years.Results: Prevalence of hepatic iron overload and fibrosis were comparable between the 2 groups. Disease-related conditions were more common in male subjects identified by health checks, but they were older. Hepatic iron overload (grades 2-4) was present in 56% and 34.5% of male and female subjects, respectively; hepatic fibrosis (stages 2-4) in 18.4% and 5.4%; and cirrhosis in 5.6% and 1.9%. Hepatic fibrosis and cirrhosis correlated significantly with the hepatic iron concentration, and except in cases of cirrhosis, there was a 7.5-fold reduction in the mean fibrosis score after phlebotomy. All subjects with cirrhosis were asymptomatic.Conclusions: Screening for hemochromatosis in apparently healthy subjects homozygous for the C282Y mutation with or without a family history reveals comparable levels of hepatic iron overload and disease. Significant hepatic fibrosis is frequently found in asymptomatic subjects with hemochromatosis and, except when cirrhosis is present, is reversed by iron removal.

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