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)

Although venesection therapy is well established for the initial depletion of iron stores in hereditary hemochromatosis, the frequency of subsequent therapy has not been clearly defined. In this study, 21 homozygotes (16 male, five female; mean age of 58, with a range of 26 to 77 years) who had completed initial venesection therapy were followed without further venesections for a mean of 4.0 years (range of 1 to 10.4 years) with iron reaccumulation assessed by annual serum ferritin concentration. Over the follow-up period, the mean rise in serum ferritin was 99 (micrograms/l)/year (range of 1.2 to 241 micrograms/l). The mean interval for the ferritin to become elevated above the normal range in 10 patients was 3.8 years. Eleven of 21 patients required no further venesection therapy over the follow-up interval. There was no significant correlation between the annual rate of ferritin increase and the age or amount of iron removed by prior venesections. These data demonstrate that monitoring body iron stores annually and the selective use of venesections if iron stores reaccumulate is a safe alternative to lifelong venesections every 2-4 months. Many homozygotes will not require reinitiation of venesection therapy for > 4 years. Annual monitoring of body iron stores with reinstitution of weekly venesection when the serum ferritin exceeds the upper limit of normal was a safe alternative to long-term maintenance venesection.
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PMID:Rate of iron reaccumulation following iron depletion in hereditary hemochromatosis. Implications for venesection therapy. 850 91

Iron deficiency severe enough to cause anemia is associated with significant morbidity while uncontrolled iron absorption which occurs in disorders such as hereditary hemochromatosis causes multiorgan failure and early death. Preliminary data from the Third National Health and Nutrition Examination Survey demonstrate that the prevalence of iron deficiency anemia in the United States is now very low. This implies that the current iron consumption is adequate for most individuals. An important unresolved question relates to the necessity for further reducing the prevalence of iron deficiency without anemia. More information is required to determine whether this lesser degree of iron deficiency is harmful. Recent survey data indicate that concomitantly with the reduced prevalence of iron deficiency there has been a rise in serum ferritin concentrations in American men and postmenopausal women. These findings have led to concern about the effectiveness of the physiological mechanisms for limiting storage accumulation in normal individuals and carriers of the hemochromatosis gene when dietary iron content is high. Furthermore, recent epidemiological observations suggest that a modest increase in iron stores (in a range previously considered safe) is a possible risk factor for ischemic heart disease and cancer; however, a causal relationship remains to be proven. Nonetheless, because there is no known benefit of high iron storage status, it seems prudent to avoid further increases in and possibly to reduce the dietary iron intake of men and postmenopausal women. Mean intake in these groups exceeds the current RDA by a significant margin. Therefore, the sources of dietary iron as well as other factors contributing to high serum ferritin values have to be defined. Also, efforts should be made to increase the awareness of professionals and the public about the possible risks of excessive dietary iron. The complexity of the Western diet and an incomplete understanding of all of the factors affecting serum ferritin concentrations make it very difficult to specify a safe upper range for daily iron intake at the present time.
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PMID:Deliberations and evaluations of the approaches, endpoints and paradigms for iron dietary recommendations. 881 5

The prevalence of homozygous hereditary hemochromatosis (HHC) is estimated at 1:250 in Caucasian adults. Little is known about ethnic subpopulations that might be at increased risk for this disease. HLA data have suggested a Celtic origin for HHC. Screening for HHC was offered to all employees of the Massachusetts Polaroid Corporation. Participants with a transferrin saturation of >55% or >45% and an elevated serum ferritin concentration on two screenings were referred for liver biopsy. The diagnosis of HHC was based on histological criteria, quantitative hepatic iron determination, hepatic iron index, and the phlebotomy requirement for iron depletion. Participants completed a questionnaire regarding their ethnic background. Two thousand two hundred ninety-four employees were screened, and 5 cases of HHC were detected. All 5 cases involved Caucasian men, yielding a prevalence of 1:395 for the Caucasian population. Four of the 5 cases were of 100% British-Irish ancestry based on the country of origin of their grandparents. Additional analysis revealed that the majority of grandparents of all 4 individuals came from Ireland or Wales. The exact two-tailed trend test showed a significant association of HHC with Celtic background (P = .012). The estimated cost of screening per patient identified was $18,041. Polaroid Corporation has a high representation of employees of British-Irish ancestry. Our data suggest that they are at high risk for developing HHC. A significant association of HHC with Celtic ancestry was found in this subpopulation, supporting the concept of a Celtic origin for this disease.
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PMID:Prevalence of hereditary hemochromatosis in a Massachusetts corporation: is Celtic origin a risk factor? 918 65

Chronic mild liver enzyme abnormalities are attributable to hereditary hemochromatosis in at least 3% of cases. Hemochromatosis formerly was diagnosed late with diabetes and hepatic and cardiac failure. Only recently have the autosomal recessive inheritance and subtle early presentations been understood. However, patients still wait many years and see many physicians before receiving a correct diagnosis. Increased serum transferrin saturation is currently the best test for detection of those likely to accumulate iron. Serum ferritin identifies those requiring treatment. When liver biopsy (controversial in asymptomatic individuals) is indicated, chemical measurement of liver iron content is helpful and therapeutic phlebotomy is the only effective treatment. Caucasian-type hemochromatosis (prevalence of 0.005) is associated with genetic abnormalities in HLA-H but also occurs in other ethnic groups. Those of African descent may have a different but also heritable iron-loading disease. Caucasian-type and to a lesser extent African iron loading are detectable early by laboratory testing. Early treatment restores normal expectations of length and quality of life in the Caucasian disease. Long-term treatment data are not yet available in African iron loading. Laboratory-initiated screening programs using unsaturated iron-binding capacity can eliminate symptomatic hemochromatosis.
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PMID:Mild liver enzyme abnormalities: eliminating hemochromatosis as cause. 926 5

A candidate gene (HFE) has been described for hereditary hemochromatosis on chromosome 6. The study of well-defined atypical hemochromatosis families using genetic markers may increase our understanding of the sensitivity and the specificity of genotyping in hemochromatosis. One hundred and thirteen Canadian families with genetic hemochromatosis were surveyed to find atypical families as possible examples of people with genetic recombinations. All families underwent clinical investigations including iron studies and HLA typing. Each individual was typed at three polymorphic microsatellite loci (D6S105, D6S1260, and D6S299) on chromosome 6. Sixteen subjects were studied for the two missense mutations described for the candidate gene for hemochromatosis (C282Y, H63D). There were eight HLA-identical siblings found in four different families (five men, three women; age range 30-72) with normal transferrin saturation and ferritin levels. There were two patients identified who were homozygous for the C282Y mutation without biochemical evidence of iron overload, and two patients with no evidence of the mutation with significant iron overload. Our conclusions are as follows: 1) finding HLA-identical siblings without iron overload does not confirm a genetic recombination, 2) difficulties in phenotypic definition of disease and the description of new iron overload syndromes that may differ from classical genetic HC cause complicated genetic studies, and 3) finding iron-loaded patients without a C282Y mutation and patients that are homozygous for the C282Y mutation without evidence of iron overload may limit the use of genotyping in population screening for hemochromatosis.
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PMID:Clinical and family studies in genetic hemochromatosis: microsatellite and HFE studies in five atypical families. 932 24

Prospective blood donors (n = 1,265, mean age 26 years) were screened for elevated serum ferritin and serum iron. Final diagnosis for hereditary hemochromatosis was made by liver iron concentration (noninvasive biomagnetometry), transferrin saturation, and 59Fe absorption in 3 male subjects. This preliminary result confirms for the first time the current frequency estimation of homozygous hemochromatosis (0.2-0.6%) in a group of young North-Germans.
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PMID:Screening for hereditary hemochromatosis in prospective blood donors. 942 15

The human leukocyte antigen (HLA)-linked iron-loading gene (HFE) associated with the autosomal recessive disorder known as hereditary hemochromatosis occurs in about 10% of subjects of European descent, most of whom are unaffected heterozygotes. In contrast, the 3 to 5 per 1,000 who are homozygotes are at risk of developing severe and potentially lethal iron overload, with damage to a number of organs, including the liver, pancreas, heart, joints, and the endocrine glands. Although the removal of the excess iron by repeated venesections is simple, effective, and safe therapy, much of the organ damage, once it has occurred, is irreversible. Because symptoms are often nonspecific, it is important for physicians in the relevant specialties to develop a high index of suspicion and to apply widely the appropriate screening tests, including transferrin saturation and serum ferritin concentration. Equally important is the detection of affected family members, who are usually siblings, before they have developed significant iron overload. In addition, screening of populations in which the prevalence of hereditary hemochromatosis is high has become an attractive and cost-effective option, especially now that the molecular structure of the HFE gene has been defined. Using this approach it is now possible to detect individuals homozygous or heterozygous for the gene using a simple polymerase chain reaction-based test. The application of this exciting new tool promises to provide fresh insights into the range of phenotypic expression in hereditary hemochromatosis. A challenge for the future will be to define the genetic or environmental factors responsible for iron overload in up to 20% of patients with clinical hemochromatosis who do not have the HFE gene.
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PMID:Hereditary hemochromatosis: etiologic, pathologic, and clinical aspects. 946 Aug 9

A 37-year-old untransfused, non-drinking man with Hemoglobin H-CS disease presented with insulin-dependent diabetes mellitus, markedly elevated serum ferritin level, and marked iron deposition in hepatocytes. He did not carry either of the two common mutations of the HLA-H gene for hereditary hemochromatosis, namely, Cys282Tyr and His68Asp, nor did he have the associated HLA marker (HLA-A3, B7 nor B-14) for the disease. Patient with HbH disease should be monitored for iron overload.
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PMID:Hemosiderosis with diabetes mellitus in untransfused Hemoglobin H disease. 946 50

Hemodialysis patients treated with recombinant human erythropoietin (rhEPO) need adequate iron supplementation to avoid rhEPO hyporesponsiveness due to iron deficiency. Low serum ferritin reflects absolute iron deficiency, whereas normal or high ferritin values in combination with low transferrin saturation (< 20%) indicate functional iron deficiency. In this study, healthy subjects (group I) were compared with intravenous (i.v.) rhEPO-treated and i.v. iron-saccharate-treated regular hemodialysis patients that were subdivided into three groups as follows: patients with serum ferritin > 100 and < 350 micrograms/L (group II), patients with ferritin < 60 micrograms/L (group III), and patients with ferritin > 650 micrograms/L but transferrin saturation < 20% (group IV). Polymorphonuclear leukocyte (PMNL) parameters (phagocytosis, intracellular killing of bacteria, oxidative metabolism, glucose uptake, intracellular calcium) for each group were compared with those of multitransfused, iron-overloaded primary hematologic patients (group V) and those of patients suffering from hereditary hemochromatosis (group VI). Compared with PMNL obtained from healthy subjects (group I), group II hemodialysis patients showed mild inhibition of phagocytosis but significant inhibition of intracellular killing of bacteria. Oxidative burst of PMNL from group II patients was also significantly reduced after stimulation in vitro. These dysfunctions were not affected by absolute iron deficiency (comparable data in group III patients). However, impairment of PMNL was markedly aggravated in group IV patients. Intracellular calcium concentration under basal conditions and after stimulation was not different. These data suggest that iron is responsible for the PMNL dysfunctions observed in group IV patients. The PMNL defect of group IV patients was comparable to group V and group VI patients with normal renal function, suggesting again a direct inhibitory effect of iron. It is concluded that hemodialysis patients with high ferritin but low serum iron and low transferrin saturation ("functional iron deficiency") display a significant impairment of fundamental PMNL functions during i.v. iron and rhEPO therapy. This may result in increased risk of infectious complications. Therefore, overtreatment of hemodialysis patients with i.v. iron should be avoided.
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PMID:Neutrophil impairment associated with iron therapy in hemodialysis patients with functional iron deficiency. 955 68

Among patients with hepatic iron overload, the distinction between hereditary hemochromatosis (HH), a common yet treatable genetic disease, and other causes of siderosis remains problematic. The recent discovery of a specific homozygous mutation (C282Y) in a novel major histocompatibility complex class I-like gene (named HLA-H or HFE) in 80% to 100% of well-characterized cases of HH suggests that direct DNA-based mutation analysis may help resolve this dilemma. To assess the clinical utility of direct HLA-H mutation analysis in a typical diagnostic setting, we measured genotypic and phenotypic parameters of iron overload in 37 subjects with biopsy-proven hepatic siderosis (2+ or greater) and in 127 healthy control subjects. The prevalence of C282Y homozygotes was significantly greater in the hepatic siderosis group (32%) than in the control group (0%), confirming the association between this homozygous mutation and hepatic iron overload. In the hepatic siderosis group, C282Y homozygotes had significantly higher hepatic iron and ferritin levels, a significantly lower prevalence of hepatitis C virus or alcoholic liver disease, but no significant difference in the saturation of serum transferrin. Of the 20 subjects with a hepatic iron index (HII) in the previously defined "hemochromatosis range" (>1.9), 9 (45%) were C282Y homozygotes. Of the 11 nonhomozygous subjects with an HII greater than 1.9 (presumed false-positive HIIs), 10 (91%) had hepatic cirrhosis compared with 3 of 9 (33%) homozygotes with an HII greater than 1.9 who had cirrhosis (P<.02). The HII thus has poor diagnostic specificity for predicting genotypic HH in patients with cirrhosis. We conclude that direct determination of the HLA-H C282Y genotype may be the single best diagnostic test for HH, particularly in patients with cirrhosis, for whom the HII is quite nonspecific.
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PMID:Hepatic iron overload: direct HFE (HLA-H) mutation analysis vs quantitative iron assays for the diagnosis of hereditary hemochromatosis. 957 64


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