Hemochromatosis genes and other factors contributing to the pathogenesis of porphyria cutanea tarda

Inherited and acquired factors have been implicated in the pathogenesis of porphyria cutanea tarda (PCT), a disorder characterized by a photosensitive dermatosis and hepatic siderosis. This study, comprising 108 patients with PCT, was intended to define the role of hemochromatosis gene (HFE) mutations in the expression of PCT and to determine the contribution of acquired factors including alcohol, hepatitis C virus (HCV), and estrogen. The 2 known HFE mutations, cysteine 282 tyrosine (Cys282Tyr) and histidine 63 asparagine (His63Asp), were detected by polymerase chain reaction, and anti-HCV immunoglobulin G was detected serologically. Liver biopsies were graded for iron content, inflammation, and fibrosis. Estimates of alcohol and estrogen use were based on a questionnaire. Of the PCT patients tested, 19% were homozygous for the Cys282Tyr mutation; controls were equal to 0.5%. The compound heterozygous genotype was detected in 7% of the PCT patients; controls were less than 1%. The transferrin saturation, serum ferritin, and liver iron burden of all PCT patients were higher than those of nonporphyric controls. The highest values were found in PCT patients homozygous for the Cys282Tyr mutation. Of the patients studied, 59% were HCV positive (compared with 1.8% of the population), and 46% consumed more than 70 g of alcohol daily. Of the female patients, 63% were ingesting estrogens. Hepatic damage was most marked in patients with the Cys282Tyr/Cys282Tyr genotype who had HCV and drank heavily. Homozygosity for the Cys282Tyr mutation and HCV are the greatest risk factors for expression of PCT, and in most patients, more than 1 risk factor was identified. It was common for patients with HCV to consume alcohol. Patients with PCT should be screened for HFE mutations and for HCV. (Blood. 2000;95:1565-1571)     

Hemochromatosis

Hemochromatosis is a common genetic disease with a wide range of clinical expression: from no symptoms to cirrhosis of the liver. The discovery of the gene has led to a genetic blood test useful in the diagnosis of hemochromatosis. Treatment by phlebotomy is simple and efficient and can prevent the development of cirrhosis, leading to a normal life expectancy.     

Hemochromatosis

Opinion Statement  

Hemochromatosis

The recent cloning of the hemochromatosis gene (HFE) and the demonstration that a single missense mutation is responsible for 90% or more of patients with the disease, have stimulated renewed interest in all aspects of this common disease. The molecular tests for identifying mutations in HFE provide improved means for diagnosis, family screening, and population screening. Moreover, the elucidation of the role of the HFE gene product will provide new insights into the regulation of normal iron absorption and iron metabolism. In addition, it is now apparent that iron, even in the modest tissue concentrations, can act as a co-factor in potentiating cell injury in other liver diseases.     

Hemochromatosis (HFE) gene mutations and hepatitis C virus infection as risk factors for porphyria cutanea tarda in Hungarian patients.

AIM: It is not clear whether the mutations in hemochromatosis (HFE) gene and hepatitis C virus (HCV) infection act independently in the pathogenesis of porphyria cutanea tarda (PCT). The prevalence of both risk factors varies greatly in different parts of the world. PCT patients from Hungary were evaluated to assess both factors. METHODS: The prevalence of C282Y and H63D mutations in the HFE gene was determined in 50 PCT patients and compared with the reported control frequencies. Furthermore, the presence of HCV infection was determined and related to the patients' HFE gene status. RESULTS: The C282Y mutation was found in 8/50 cases (three homozygotes and five heterozygotes), with an 11% allele frequency (vs. 3.8% control) (P<0.05). Seventeen patients were heterozygous, one was homozygous for the H63D mutation, allele frequency 19%, which did not differ significantly from the reported control prevalence of 12.3%. Twenty-two patients (44%) were HCV-RNA positive; six out of them were heterozygous for H63D mutation, one only for the C282Y mutation and one was compound heterozygous for both mutations. CONCLUSION: HCV infection and HFE C282Y mutation may probably be independent predisposing factors for development of PCT in Hungarian patients.     

HFE Hemochromatosis and Hepatic Sarcoid

A 57-year-old white woman had serum ferritin 793 ng/mL, HFE C282Y homozygosity, elevated serum angiotensin-converting enzyme (ACE) levels, 3 + hepatocyte iron, cirrhosis, hepatic granulomas, and portal hypertension. Her 37-year-old son had ferritin 869 ng/mL, C282Y/wt, elevated ACE levels, 2 + hepatocyte iron, bridging fibrosis, and hepatic granulomas. Her daughters had HFE C282Y/H63D and C282Y/wt, respectively; neither had a hemochromatosis phenotype, sarcoid, or severe liver disease. All 4 subjects had nonalcoholic hepatic steatosis. Sarcoid did not segregate with the human leukocyte antigen-A and -B haplotype shared by the proband, her son, and 1 daughter. Phlebotomy to achieve iron depletion in the proband and her son yielded 1.6 and 1.5 g iron, respectively; their ACE levels remained elevated. We reviewed previous reports of 4 patients with hemochromatosis and sarcoid. We conclude that a combination of sarcoid, steatosis, and excessive hepatocyte iron caused cirrhosis or hepatic fibrosis in the proband and her son.     

Hemochromatosis and pyruvate kinase deficiency

Hemochromatosis has been reported in several patients with chronic hemolytic anemia due to pyruvate kinase deficiency. We describe here a further patient with such an association and review the literature on the subject. We hypothesize that iron overload may occur in patients with pyruvate kinase deficiency who are also carriers of the hereditary hemochromatosis gene.     

Hemochromatosis: diagnosis and management

HH should be distinguished from the other syndromes of iron overload. Many patients with HH have abnormal serum iron values before the development of any significant symptoms or clinical findings, and liver biopsy is less important in these patients. HFE mutation analysis has strengthened our ability to diagnose HH accurately and is useful in family studies. HFE mutations may play a contributory role in some patients with PCT, NASH, or chronic HCV. Generalized population screening for HH may someday become a reality and lead to the identification and treatment of more patients before they have tissue damage or increased morbidity. With the identification of the HFE gene, we are beginning to unravel many of the mysteries of both normal iron absorption and the disorder of iron metabolism found in patients with HH.     

Hemochromatosis in Ireland and HFE

ABSTRACT: Sixty patients diagnosed with hereditary hemochromatosis with grade 3 or 4 hepatic iron overload and 18 patients diagnosed with hereditary hemochromatosis who had less than grade 3 hepatic iron overload were examined for theHFEgene mutations, 845A (C282Y) and 187G (H63D). Control samples were obtained from 109 randomly selected individuals. Fifty-six of 60 unrelated hereditary hemochromatosis patients (93%) with grade 3 or 4 hepatic iron deposition were homozygous for the C282Y mutation. Fourteen of the 18 hereditary hemochromatosis patients with <3+ iron deposition (76%) were homozygous for the C282Y mutation. Three of 8 patients who were heterozygous for the C282Y mutation were also heterozygous for the H63D mutation. Thirty-one of 109 control individuals were heterozygous for the C282Y mutation and 27 were heterozygous for the H63D mutation. Our finding that 93% of hereditary hemochromatosis patients who fulfil standard diagnostic criteria are homozygous for the C282Y mutation provides clear evidence that this mutation is strongly associated with hereditary hemochromatosis. The allele frequency of 14% for the C282Y mutation in our control population is the highest reported and supports the hypothesis of a Celtic origin for the hereditary hemochromatosis gene.