Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The HFE gene, a member of the class-I transplantation antigen gene family, is responsible for hereditary hemochromatosis, one of the most common inherited diseases in individuals of European descent. Patients exhibit predictable changes in iron homeostasis, including elevations in both transferrin saturation and serum ferritin levels. A subset of patients progress to overt clinical sequelae, resulting from iron overload. A hallmark of the disease is increased absorption of iron by the intestine. Although the HFE protein appears to modulate the function of the transferrin receptor in vitro, its precise role in vivo remains obscure. With multiple cell types involved in iron metabolism, the function of HFE is likely to be complex.
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PMID:The enigmatic role of the hemochromatosis protein (HFE) in iron absorption. 1265 33

Diabetes mellitus (DM) is an important risk factor for the development of cardiovascular disease. Extensive clinical, epidemiologic, and basic studies suggest that excessive tissue iron stores may contribute to the occurrence and complications of DM. Secondary diabetes occurs in inherited pathologic iron overload syndromes of European- and African-derived populations and is an established complication of transfusional iron overload. Epidemiologic studies have repeatedly shown positive correlation between levels of serum ferritin and those of fasting glucose, insulin, and glycosylated hemoglobin. Iron reduction therapy in hereditary hemochromatosis and transfusional iron overload is associated with improved glucose tolerance and reduced incidence of secondary diabetes. Trials of iron reduction therapy in diabetes mellitus, although limited and inconclusive, have shown clinical improvement in some patients. The current article reviews evidence suggesting that tissue iron contributes to DM and its complications and presents preliminary data that emphasize the potential importance of iron overload in DM of African Americans.
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PMID:Potential role of increased iron stores in diabetes. 1281 Dec 29

When suspecting an iron overload condition, the transferrin saturation levels should be determined. Levels higher than 45% and serum ferritin in men and postmenopausal women exceeding 200 microg/l confirm the iron overload. Afterwards, the HFE protein genotype should be determined. If it is C282Y or C282Y/H63D, the diagnosis of hereditary hemochromatosis can be accepted as the cause of the iron overload. In the absence of said genotypes, the overload is secondary or not related to the HFE protein. In hereditary hemochromatosis, the degree of iron overload and organic lesions must be established. Liver biopsies are very useful for obtaining said information and for the first case, the determination of serum ferritin is very useful. When less than 1000 microg/l, normal transaminases and no hepatomegalies, a treatment can be started without the need for a liver biopsy. In absence of anemia, the treatment is based on phlebotomies, 400-500 ml a week until obtaining depletion of excess iron. In presence of anemia, the treatment is based on chelating agents, preferably subcutaneous administered 8 hours a day.
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PMID:Strategy for diagnosis and management in iron overload. 1282 22

Hereditary hemochromatosis is a common inherited disorder characterized by iron overload. A single mutation (C282Y) in the HFE gene is present in 80-95% of cases in populations of northern European extraction. The disorder presents a large phenotypic heterogeneity, and its expression can be influenced by environmental factors. This 1977-2002 study aimed to identify the influence of alcohol consumption on expression of the disease. The authors retrospectively registered 378 C282Y-homozygous patients treated in a blood center of western Brittany, France. In this cohort, 33 patients reported excessive alcohol consumption (8.7%). Those subjects presented significantly increased iron parameters (serum ferritin: 1745.2 vs. 968.7 microg/liter, p< 0.0001; serum iron: 39.9 vs. 36.0 micromol/liter, p = 0.0040; transferrin saturation: 87.1 vs. 80.1%, p = 0.0071) and elevated liver enzymes (alanine aminotransferase: 66.3 vs. 41.1 IU/liter, p = 0.0003; aspartate aminotransferase: 56.2 vs. 34.9 IU/liter, p = 0.0002). Their risk of skin pigmentation was also higher (odds ratio = 3.4, p = 0.0006). Results remained unchanged after adjustment. This study provides precise quantitative data about the impact of alcohol on expression of hereditary hemochromatosis in C282Y-homozygous patients. Excessive alcohol consumption accentuates disease expression and therefore the risk of cirrhosis and cancer. Consequently, these patients should be encouraged to consume very moderate quantities of alcohol.
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PMID:Hereditary hemochromatosis: effect of excessive alcohol consumption on disease expression in patients homozygous for the C282Y mutation. 1285 Dec 25

The mechanisms by which the hereditary hemochromatosis protein, HFE, decreases transferrin-mediated iron uptake were examined. Coimmunoprecipitation studies using solubilized cell extracts demonstrated that transferrin (Tf) competed with HFE for binding to the transferrin receptor (TfR) similar to previous in vitro studies using soluble truncated forms of HFE and the TfR. At concentrations of Tf approaching those found in the blood, no differences in Tf binding to cells were detected, which is consistent with the lower binding constant of HFE for TfR versus Tf. However, cells expressing HFE still showed a decrease in Tf-mediated iron uptake at concentrations of Tf sufficient to dissociate HFE from the TfR. These results indicate that the association of HFE with TfR is not essential for its ability to lower intracellular iron stores. To test the effect of HFE on lowering intracellular iron levels independently of its association with TfR, a mutated HFE (fW81AHFE) that shows greatly reduced affinity for the TfR was transfected into tetracycline-controlled transactivator HeLa cells. HeLa cells expressing fW81AHFE behaved in a similar manner to cells expressing wild-type HFE with respect to decreased intracellular iron levels measured by iron regulatory protein gel-shift assays and ferritin levels. The results indicate that HFE can lower intracellular iron levels independently of its interaction with the TfR.
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PMID:Mechanisms of HFE-induced regulation of iron homeostasis: Insights from the W81A HFE mutation. 1287 82

This report describes a case of sporadic porphyria cutanea tarda involving a 38-year-old Moroccan man. Clinical diagnosis was based on characteristic features, i.e., facial hypertrichosis and bullous lesions lasting four months during the summer of 2000 followed by macular scarring on the dorsal surfaces on the hands. Three well-known precipitating factors were noted, i.e., sun, ethanol and hepatitis C virus infection. Laboratory diagnosis was based on dark red urine and elevated serum and urine uroporphyrin levels. Enhanced uroporphyrin production was due to urodecarboxylase deficiency in the liver. Urodecarboxylase activity in red blood cells and serum ferritin level were normal. The patient is heterozygous for the His63Asp HFE gene mutation associated with hereditary hemochromatosis. The photoprotective effect of melanin in this dark-skinned patient failed to offset uroporphyrin-induced photosensitivity. Avoidance of sun, ethanol and phlebotomy have prevented recurrences.
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PMID:[Sporadic porphyria cutanea tarda: a case report in a Moroccan man]. 1291 Jun 60

The measurement of hepatic iron overload is of particular interest in cases of hereditary hemochromatosis or in patients subject to periodic blood transfusion. The measurement of plasma ferritin provides an indirect estimate but the usefulness of this method is limited by many common clinical conditions (inflammation, infection, etc). Liver biopsy provides the most quantitative direct measurement of iron content in the liver but the risk of the procedure limits its acceptability. This work studies the feasibility of a magnetic induction (MI) low-cost system to measure liver iron overload. The excitation magnetic field (B0, frequency: 28 kHz) was produced by a coil, the perturbation produced by the object (deltaB) was detected using a planar gradiometer. We measured ten patients and seven volunteers in supine and prone positions. Each subject was moved in a plane parallel to the gradiometer several times to estimate measurement repeatability. The real and imaginary parts of deltaB/B0 were measured. Plastic tanks filled with water, saline and ferric solutions were measured for calibration purposes. We used a finite element model to evaluate the experimental results. To estimate the iron content we used the ratio between the maximum values for real and imaginary parts of deltaB/B0 and the area formed by the Nyquist plot divided by the maximum imaginary part. Measurements in humans showed that the contribution of the permittivity is stronger than the contribution of the permeability produced by iron stores in the liver. Defined iron estimators show a limited correlation with expected iron content in patients (R < or = 0.56). A more precise control of geometry and position of the subjects and measurements at multiple frequencies would improve the method.
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PMID:Measurement of liver iron overload by magnetic induction using a planar gradiometer: preliminary human results. 1500 25

Iron is essential for life in almost all organisms and, in mammals, is absorbed through the villus cells of the duodenum. Using a human colonic carcinoma cell line that has many duodenal characteristics, HT29, we show that genes involved in intestinal iron transport are endogenously expressed. When stably transfected to express the hereditary hemochromatosis protein HFE these cells have increased ferritin levels. We demonstrate that this is not due to an effect on the transferrin (TF)-mediated iron uptake pathway but rather due to inhibition of iron efflux from the cell. The effect of HFE was independent of its interaction with TF receptor 1 as indicated by similar results using both the wild type HFE and the W81A mutant that binds TF receptor 1 with greatly reduced affinity. HFE expression did not affect the mRNA levels of most of the genes involved in iron absorption that were tested; however, it did correspond to a decrease in hephaestin message levels. These results point to a role for HFE in inhibition of iron efflux in HT29 cells. This is a distinct role from that in HeLa and human embryonic kidney 293 cells where HFE has been shown to inhibit TF-mediated iron uptake resulting in decreased ferritin levels. Such a distinction suggests a multifunctional role for HFE that is dependent upon expression levels of proteins involved in iron transport.
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PMID:Expression of the hereditary hemochromatosis protein HFE increases ferritin levels by inhibiting iron export in HT29 cells. 1504 62

The progression rate of iron overload in hereditary hemochromatosis in individuals in the general population is unknown. We therefore examined in the general population iron overload progression rate in C282Y homozygotes. Using a cohort study of the Danish general population, The Copenhagen City Heart Study, we genotyped 9174 individuals. The 23 C282Y homozygotes identified were matched to 2 subjects each of 5 other HFE genotypes with respect to sex, age, and alcohol consumption. As a function of biologic age, transferrin saturation increased from 50% to 70% from 25 to 85 years of age and from 70% to 80% from 35 to 80 years of age in female and male C282Y homozygotes, respectively. Equivalently, ferritin levels increased from 100 to 500 microg/L and decreased from 800 to 400 microg/L in female and male C282Y homozygotes. As a function of 25 years follow-up irrespective of age, transferrin saturation and ferritin levels increased slightly in male and female C282Y homozygotes. None of the C282Y homozygotes developed clinically overt hemochromatosis. In conclusion, individuals in the general population with C282Y homozygosity at most demonstrate modest increases in transferrin saturation and ferritin levels, and clinically overt hemochromatosis is rare. Therefore, C282Y homozygotes identified during population screening, and not because of clinically overt hemochromatosis, at most need to be screened for manifestations of hemochromatosis every 10 to 20 years.
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PMID:Hemochromatosis mutations in the general population: iron overload progression rate. 1507 Jun 63

In this study we screened 3060 consecutive blood donors for an unbound iron-binding capacity level of <28 microM and then performed HFE mutation analysis in these subjects. Sixty-five of the 75 subjects with a low initial unbound iron-binding capacity (all had normal ferritin levels) came back and only 5 (8%) had a low fasting unbound iron-binding capacity. Mutational analysis revealed H63D heterozygosity in two of five subjects. Four of five subjects had liver biopsy indication and none had increased liver iron. HFE genotyping of 60 subjects with a low initial but normal fasting unbound iron-binding capacity revealed heterozygote H63D in seven (11.6%). No allelic variant of position 282 or 63 was found in three previously diagnosed patients with hereditary hemochromatosis. In conclusion, full phenotypic expression of hereditary hemochromatosis is very rare in Turkey. The absence of HFE mutations in three patients with hereditary hemochromatosis suggests that hereditary hemochromatosis in Turkey occurs without common HFE mutations.
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PMID:Screening for hemochromatosis in Turkey. 1513 95


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