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PubMed1998

Iron overload in bone marrow transplant recipients.

We examined the degree of hepatic iron overload in patients receiving marrow transplant for hematologic malignancy and evaluated a new method of morphometric analysis of marrow iron content as a means of estimating hepatic iron stores in these patients. The iron content of marrow and liver specimens from 10 consecutive patients who died between 50 and 100 days after transplant was determined by spectrophotometry. Their mean age was 34.9 years (range 10-59). The mean time to death from disease onset was 2.2 years (0.5-8.7). Patients had received 30.2 +/- 17.4 units of red cells during the transplant period and 47.6 +/- 25.9 red cell units from diagnosis to death. The median hepatic iron concentration (HIC) was 4307 microg/g dry weight (range 1832-13120; normal 530-900) and the median hepatic iron index (HIC (micromol/g dry weight/age (years)) was 3.85 (0.76-8.14). The median biochemical marrow iron content was 1999 microg/g dry weight (range 932-3942). Morphometric analysis of the marrow iron content was performed on digital photomicrographs of a single Prussian blue-stained section of marrow. Strong correlations were demonstrated between morphometric marrow iron content and (1) biochemical marrow iron content (r = 0.8, P= 0.006) and (2) biochemical hepatic iron index (r = 0.82, P = 0.004). We conclude that marrow transplant recipients have a high liver iron content at 50-100 days post transplant with the hepatic iron index in the hereditary hemochromatosis range. Computerized morphometric marrow iron determination is a readily available means of estimating hepatic iron stores in these patients.

Adolescent↗
PubMed1996

Associations of iron overload in Africa with hepatocellular carcinoma and tuberculosis: Strachan's 1929 thesis revisited.

We analyzed data from the first study of iron overload in Africans, conducted between 1925 and 1928, to determine whether this common condition is associated with death from hepatocellular carcinoma and/or tuberculosis. In the original study, necropsies were performed on 714 adult blacks from southern Africa. Hepatic and splenic iron levels were measured semiquantitatively in 604 subjects and one of five iron grades was assigned. We examined death from hepatocellular carcinoma or from tuberculosis and the variables of age, sex, the presence of cirrhosis or other diagnoses that might be influenced by iron status, and tissue iron grades. Nineteen percent of men and 16% of women had the highest grade of hepatic iron. After adjustment for the presence of cirrhosis, hepatic iron grade was the variable most significantly associated with death from hepatocellular carcinoma (P = .021). The odds of death from hepatocellular carcinoma in subjects with the highest grade of hepatic iron was 23.5 (95% confidence interval, 2.1 to 225) times the odds in subjects with the three lowest grades. Splenic iron was the variable most significantly associated with death from tuberculosis (P <.0001). The odds of death from tuberculosis with the highest grade of splenic iron was 16.9 (4.8 to 59.9) times the odds with the two lowest grades. These findings suggest that iron overload in black Africans may be a risk factor for death from hepatocellular carcinoma and for death from tuberculosis.

Adult↗
PubMed2000

The S65C mutation in Spain. Implications for iron overload screening.

Hereditary hemochromatosis is related to mutations of the HFE gene. The role of the S65C mutation of this gene was evaluated in a Spanish population, consisting of 100 controls and 41 patients who had resulted positive to screening for iron overload. Only one patient was heterozygous for the S65C mutation, so the S65C mutation is infrequent in our area. Nevertheless, it is advisable to search for this mutation in cases with iron overload and heterozygosity for the C282Y or H63D mutations of the HFE gene.

Case-Control Studies↗
PubMed2006

Hereditary iron overload: update on pathophysiology, diagnosis, and treatment.

Hereditary hemochromatosis, a very common genetic defect in the Caucasian population, is characterized by progressive tissue iron overload which leads to irreversible organ damage if it is not treated timely. The elucidation of the molecular pathways of iron transport through cells and its control has led to the understanding of various genetic iron-loading conditions. Four types of inherited iron overload have been recognized: type 1, the most common form with an autosomal recessive inheritance, is associated with mutations in the HFE gene on chromosome 6; type 2 (juvenile hemochromatosis) is an autosomal recessive disorder with causative mutations identified in the HJV gene (subtype A) on chromosome 1 and the HAMP gene (subtype B) on chromosome 19; type 3 has also an autosomal recessive inheritance with mutations in the TfR2 gene on chromosome 3; type 4 is an autosomal dominant condition with heterozygous mutations in the ferroportin 1 gene on chromosome 2. In this review, the genetics, pathophysiology, diagnosis, clinical features, and management of these different types of hereditary hemochromatosis are briefly discussed.

Antimicrobial Cationic Peptides↗
PubMed1979

Changing patterns of dietary iron overload in black South Africans.

Over the last 17 years there has been a significant reduction in the prevalence and severity of dietary iron overload in urban blacks of Johannesburg. This is attributed to a decrease in the consumption of traditionally brewed beer of high iron content over this period. A 40% reduction was found in hepatic iron concentrations measured in necropsy specimens from 248 male patients who died in 1976 as compared with 220 who died in 1959 and 1960. While hepatic iron concentrations rose with age in both groups there was no evidence of iron accumulation during the period between the two studies. Hepatic iron concentrations measured in 345 female subjects were many fold less than those of males and the 1976 group did not differ significantly from the 1959 to 1960 group. A paradoxical increase in the prevalence of portal fibrosis and cirrhosis was seen and may be due to the effects of increased ingestion of spirits and fortified wine in recent years. Iron overload was significantly greater in males with carcinoma of the esophagus and in those with idiopathic heart failure when compared to subjects who died of other causes. This suggests excessive exposure of these subjects to traditionally brewed beverages and the adulterants present in them.

Adult↗
PubMed1987

Screening test for iron overload.

It is presently estimated that 2-3/10(3) people living in the United States are homozygous for the iron-loading gene and are thereby susceptible to severe iron overload. The complications of this disorder can be prevented if recognized in the asymptomatic precirrhotic stage. We have developed a simple, inexpensive screening method for its early laboratory detection based on the fact that one of the earliest laboratory manifestations of hemochromatosis is a reduction in unsaturated iron-binding capacity. The sequential addition of a small measured quantity of saturating iron and bathophenanthroline disulfonate will result in color with highly saturated but not with normal sera. This screening test almost completely differentiated between 40 normal individuals and 40 patients with iron overload (as defined by a transferrin saturation greater than 55%). The test provides a cost-effective method for screening large segments of the population to detect this genetic disorder.

Adult↗
PubMed1983

Iron overload in mild sideroblastic anaemias.

Life-threatening iron overload may occur without severe anaemia in patients with sideroblastic disorders. Assessment of erythroid expansion in bone-marrow aspirates may be as useful as ferrokinetic studies in predicting both the risk of iron loading and the need for prophylactic phlebotomy or iron-chelation therapy.

Adult↗
PubMed1994

Iron overload cardiomyopathies: new insights into an old disease.

Iron overload cardiomyopathy is an old disease that has evolved from a rare undiagnosable and untreatable condition to a now much more common, diagnosable, and potentially treatable condition. Pathologically it is due to a direct free iron effect on the myocytes, and not due to interstitial infiltration. This also implies that the disease process is reversible if the tissue iron concentration can be controlled. The advent of magnetic resonance imaging and future genetic identification can identify the population at risk. Chelation therapy, including newer forms of oral chelators, likely will be more commonly available to benefit an ever increasing number and spectrum of the population. Further active research will be needed to improve our pathophysiological understanding and clinical treatment of this increasingly common condition.

Cardiomyopathies↗
PubMed2006

Molecular and clinical correlates in iron overload associated with mutations in ferroportin.

Mutations in ferroportin (Fpn) result in iron overload. We correlate the behavior of three Fpn mutants in vitro with patients' phenotypes. Patients with Fpn mutations A77D or N174I showed macrophage iron loading. In cultured cells, FpnA77D did not reach the cell surface and cells did not export iron. Fpn mutant N174I showed plasma membrane and intracellular localization, and did not transport iron. Fpn mutation G80S was targeted to the cell surface and was transport competent, however patients showed macrophage iron. We suggest that FpnG80S represents a class of Fpn mutants whose behavior in vitro does not explain the patients' phenotype.

Amino Acid Substitution↗
PubMedDate not supplied

The GRACILE syndrome, a neonatal lethal metabolic disorder with iron overload.

GRACILE syndrome (Fellman syndrome, MIM 603358), an autosomal recessive metabolic disorder of the Finnish disease heritage, has been diagnosed in 25 infants of 18 families. The incidence is at least 1/47,000 in Finland. The main findings are fetal growth retardation, Fanconi type aminoaciduria, cholestasis, iron overload (liver hemosiderosis, hyperferritinemia, hypotransferrinemia, increased transferrin iron saturation, and free plasma iron), profound lactic acidosis, and early death. The pathophysiology of the metabolic disturbance is unsolved. No significant deficiency of complex III activity of respiratory chain has been found, although we recently showed that the underlying genetic cause is a missense mutation (S78G) in the BCS1L gene and other mutations in that gene have been associated with complex III deficiency. BCS1L encodes a mitochondrial protein, acting as a chaperone in the assembly of complex III. Iron accumulation in liver, a typical feature being less abundant with increasing age, might be a primary abnormality or a secondary phenomenon due to liver dysfunction. In order to decrease the iron overload, three infants have been repeatedly treated with apotransferrin followed by exchange transfusion. Improvement in iron biochemistry occurred, but no clear beneficial effect on the clinical condition was found. Further studies will elucidate the role of iron in the pathophysiology of the disease.

ATPases Associated with Diverse Cellular Activitie↗
PubMed2000

[Iron overload and liver diseases (except for hemochromatosis and dysmetabolic hepatosiderosis].

Iron accumulation in the liver is frequently observed in hepatic diseases whatever their etiologies. In the majority of cases, there is no true overload, and iron accumulation corresponds to deposits in macrophages secondary to iron release from damaged hepatocytes. More rarely, namely in severe cirrhosis, there is a true overload, which is probably related to iron intestinal hyperabsorption. In such case, the site of iron excess is hepatocytic. Except for hemochromatosis, mutations of HFE gene do not play a major role in iron overload. In chronic liver diseases, iron overload could favor the development of hepatocellular carcinoma, even in the absence of cirrhosis.

Hepatitis, Viral, Human↗
PubMed1993

Pyridoxine responsive hereditary sideroblastic erythropoiesis and iron overload: two microcytic subpopulations in the affected male, one normocytic and one microcytic subpopulation in the obligate female carrier.

Mild hepatic iron overload has been demonstrated by magnetic susceptibility measurements in a 22-year-old man with hereditary sideroblastic erythropoiesis despite hemoglobin levels in the normal range and a normal erythropoietin level. His grandfather's sideroblastic anemia has been found to be responsive to pyridoxine; his mother's hemoglobin has persisted in the normal range but red cell volume distribution analysis demonstrated two subpopulations; 30% with estimated geometric mean of 68 fl and 70% an estimated mean of 93 fl. Red cell distribution analysis of the grandson demonstrated two microcytic subpopulations; 46% with an estimated geometric mean of 45 fl and 54% an estimated mean of 70 fl. A therapeutic regimen is outlined to reduce to normal his iron stores and to prevent the future development of excessive iron overload.

Adolescent↗
PubMed1998

Major histocompatibility complex class I associations in iron overload: evidence for a new link between the HFE H63D mutation, HLA-A29, and non-classical forms of hemochromatosis.

The present study is an analysis of the frequencies of HFE mutations in patients with different forms of iron overload compared with the frequencies found in healthy subjects from the same region. The frequencies of HLA-A and -B antigens and HLA haplotypes were also analyzed in the same subjects. The study population included: 71 healthy individuals; 39 genetically and clinically well-characterized patients with genetic hemochromatosis (HH); and 25 patients with non-classical forms of iron overload (NCH), excluding secondary hemochromatosis. All subjects were HLA-typed and HFE-genotyped by the oligonucleotide ligation assay (OLA). The gene frequencies found for the C282Y and H63D mutations of HFE were respectively: 0.03 and 0.23 in healthy individuals, 0.86 and 0.04 in HH patients, and 0.08 and 0.48 in NCH patients. An expected significant association between HH and HLA-A3 was observed, which was found to be in linkage disequilibrium with the C282Y mutation. A new association was seen, however, between HLA-A29 and NCH, in linkage disequilibrium with the H63D mutation. Again as expected, the HLA-B antigen B7 was associated with HH in linkage disequilibrium with HLA-A3. In addition, the HLA-B antigen B44 was found to be associated with NCH but not in linkage disequilibrium with either A29 or the H63D mutation. In conclusion, a new association of the HFE H63D mutation with forms of hemochromatosis other than HH and a new association between the HLA phenotype A29 and the HFE H63D mutation were found in the same patients. These findings reinforce evidence for the involvement of the major histocompatibility class I in iron metabolism, supporting the notion of a physiological role for the immunological system in the regulation of iron load.

Adult↗
PubMed1998

Is there a link between African iron overload and the described mutations of the hereditary haemochromatosis gene?

Over 80%, of Caucasian patients with hereditary haemochromatosis are homozygotes for a C282Y mutation in the HFE gene on chromosome 6. Recent evidence suggests that a genetic factor may also be involved in the pathogenesis of African iron overload, although the locus has not been described. PCR analysis of DNA from 25 southern Africans, identified by segregation analysis as having a high probability of carrying the putative African iron-loading gene, failed to identify any subjects with the C282Y mutation. The possible genetic defect in African iron overload appears to be different from that described in most cases of hereditary haemochromatosis in Caucasians.

Adult↗
PubMed2006

Oral chelators deferasirox and deferiprone for transfusional iron overload in thalassemia major: new data, new questions.

For nearly 30 years, patients with transfusional iron overload have depended on nightly deferoxamine infusions for iron chelation. Despite dramatic gains in life expectancy in the deferoxamine era for patients with transfusion-dependent anemias, the leading cause of death for young adults with thalassemia major and related disorders has been cardiac disease from myocardial iron deposition. Strategies to reduce cardiac disease by improving chelation regimens have been of the highest priority. These strategies have included development of novel oral iron chelators to improve compliance, improved assessment of cardiac iron status, and careful epidemiologic assessment of European outcomes with deferiprone, an oral alternative chelator available for about a decade. Each of these strategies is now bearing fruit. The novel oral chelator deferasirox was recently approved by the Food and Drug Administration (FDA); a randomized clinical trial demonstrates that deferasirox at 20 to 30 mg/kg/d can maintain or improve hepatic iron in thalassemia as well as deferoxamine. A randomized trial based on cardiac T2* magnetic resonance imaging (MRI) suggests that deferiprone can unload myocardial iron faster than deferoxamine. Retrospective epidemiologic data suggest dramatic reductions in cardiac events and mortality in Italian subjects exposed to deferiprone compared with deferoxamine. These developments herald a new era for iron chelation, but many unanswered questions remain.

Administration, Oral↗
PubMed1990

Iron overload in untransfused patients with hemoglobin H disease.

Two Chinese patients with hemoglobin (Hb) H disease without a history of blood transfusion developed iron overload at the age of 45 and 53 years, respectively. Human leukocyte antigen (HLA) system types of these 2 patients were A19, A11, B13, B62 and A2, A24, BW55, respectively, which are not related to the common haplotypes for idiopathic hemochromatosis. Since severe iron loading is a rare clinical manifestation in untransfused patients with Hb H disease, the iron overload in both patients may be due to environmental or underlying genetic factors.

Humans↗
PubMed2006

Impact of hemochromatosis screening in patients with indeterminate results: the hemochromatosis and iron overload screening study.

PURPOSE: Assess the quality of life impact of receiving indeterminate test results for hemochromatosis, a disorder involving HFE genetic mutations and/or elevated serum transferrin saturation and ferritin. METHODS: The study sample was from the Hemochromatosis and Iron Overload Screening Study, a large observational study of hemochromatosis among primary care patients in the US and Canada using HFE genotype and serum transferrin saturation and ferritin screening. Study subjects included 2,304 patients found with hemochromatosis risk of uncertain clinical significance. Assessed was SF-36 general health and emotional well-being before screening and six weeks after participants received their test results. Health worries were assessed after screening. RESULTS: Of the study subjects, 1,268 participants (51.5%) completed both assessments. Compared to normal controls, those with HFE mutations or elevated serum transferrin saturation and ferritin levels of uncertain significance were more likely to report diminished general health and mental well-being, and more health worries. These effects were associated with participants' belief of having tested positive for hemochromatosis or iron overload. CONCLUSION: Notification of indeterminate results from screening may be associated with mild negative effects on well-being, and might be a potential participant risk in screening programs for disorders with uncertain genotype-phenotype.

Adult↗
PubMed1994

New advances in iron metabolism, iron deficiency, and iron overload.

Rapid advances were made in understanding the molecular and cellular bases of iron metabolism and its disorders. Molecular mechanisms for the cellular uptake, storage, and utilization of iron were clarified in investigations of the structure and functions of transferrin, transferrin receptor, ferritin, erythroid delta-aminolevulinic acid synthase, and the RNA-binding protein termed the iron responsive-element binding protein. Evidence was obtained that a nuclear DNA-binding protein, NF-E2, may be involved in the regulation of both hemoglobin synthesis in erythroid cells and of iron absorption in the intestine. Clinically, progress was made in improving the diagnosis and management of both iron deficiency and iron overload, with studies of the usefulness of serum transferrin receptor measurements, of a new therapeutic preparation of iron using a "gastric delivery system," and of the development of new orally active iron-chelating agents.

Anemia, Iron-Deficiency↗