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Screening for hemochromatosis in children of homozygotes: prevalence and cost-effectiveness.

Although hereditary hemochromatosis is an autosomal recessive disease, most homozygotes are concerned with the genetic implications for their children. The optimal age for testing children and the cost implications of screening their children have not been clearly established. A clinical database consisting of 255 children from families with at least one homozygote is used to assess the prevalence of homozygotes among children of homozygous parents and to review the biochemical abnormalities and life-threatening symptoms in these young adults. Decision analysis is used to estimate the cost and utility of screening children of a homozygous parent. Eleven homozygotes were discovered among children of homozygotes. Only one male had a life-threatening event, cirrhosis. Decision analysis estimated cost saving of $12 per child screened ($ net present value) and a saving of 10 quality-adjusted days per child screened at age 10 years compared with not screening. If screening began at age 20 years, there is a cost saving of $65 per child screened. Sensitivity analysis showed that the major factors influencing cost savings were the cost of venesections, sensitivity and specificity of the screening tests, and prevalence of disease. Because the prevalence of hemochromatosis is higher in children of homozygotes than in the general population, screening with transferrin saturation and ferritin as early as age 10 years is recommended. Savings are augmented if the cost per venesection is eliminated by allowing hemochromatosis patients to become voluntary blood donors.

Adolescent↗

Neonatal hemochromatosis: a case report.

Hemochromatosis is the excess accumulation of iron in tissue affecting a variety of organ systems leading to hepatic fibrosis and multiorgan system failure. When excess iron accumulation occurs in utero, as with neonatal hemochromatosis, the infant may be stillborn or present with advanced, overwhelming liver disease. Hepatic failure in the newborn encompasses a wide variety of disease entities, and formulation of a differential diagnosis presents a challenge for the clinician. This article reviews one case of neonatal hemochromatosis that was diagnosed and successfully treated. Iron metabolism and overload are discussed, as well as clinical manifestations, current treatment, and the potential for prenatal diagnosis in the future.

Diagnosis, Differential↗

Prevalence of heterozygotes for hemochromatosis in the white population of the United States.

In previous studies, the prevalence of HLA-linked hemochromatosis, thought to be the most common genetic illness in whites, has been estimated by identifying homozygotes in the population. Because not all homozygotes express the disease phenotypically, the accuracy of these estimates is uncertain. We analyzed the distribution of transferrin saturation values in the second National Health and Nutrition Examination Survey to estimate the prevalence of hemochromatosis heterozygotes in the US population. After removing values for possible homozygotes, two populations were present (P < .01 for each gender). When weighted to reflect the US adult white male population as a whole, a proportion of 850 per 1,000 (95% confidence interval, 0.81 to 0.89) were included in a population with a lower mean saturation of 29.7% (29.1% to 30.3%), whereas 150 per 1,000 (0.11 to 0.19) comprised a population with a higher mean saturation of 47.0% (45.1% to 49.0%). Similar results were found for the female population. The gene frequencies were estimated to be 0.081 from the male population and 0.070 from the female population corresponding to prevalences of homozygotes of 6.6 and 4.8 per 1,000, respectively. Our results confirm that the gene for hemochromatosis is common.

Adolescent↗

Preneoplastic significance of hepatic iron-free foci in genetic hemochromatosis: a study of 185 patients.

Sublobular nodules of hepatocytes free of iron or exhibiting much less iron than the surrounding parenchyma, referred to in this study as iron-free-foci, are frequently found in the livers of patients with genetic hemochromatosis complicated by hepatocellular carcinoma. To test the hypothesis that such nodules are preneoplastic lesions, iron-free foci were sought in the initial liver biopsy specimens of 185 patients with untreated and uncomplicated genetic hemochromatosis. Iron-free foci were found in 14 (7.6%) patients, all men, aged from 38 to 76 yr, with heavy iron overload and with fibrosis or cirrhosis. Twelve patients with iron-free foci were followed for 0.9 to 15 yr (7 +/- 6 yr). In six (50%), HCC developed, compared with 2 (8%) from a control group consisting of 24 patients without IFF matched according to age, sex, degree of fibrosis, liver iron amount and follow-up duration. The mean number of iron-free foci per iron-free foci-positive specimen was 3.2 +/- 2.1. Ten patients had dysplastic aspects in their iron-free foci, and four had intrahepatocytic iron-positive inclusions at the periphery of iron-free foci. Proliferative cell nuclear antigen was positive in 75% of iron-free foci and in 24% +/- 21% of hepatocyte nuclei in iron-free foci. This study clearly demonstrates that iron-free foci are proliferative lesions and strongly suggests that such nodules are preneoplastic foci. Therefore the finding of IFF in the initial liver biopsy specimen from a patient with genetic hemochromatosis should lead to regular screening for hepatocellular carcinoma.

Adult↗

Differentiation between heterozygotes and homozygotes in genetic hemochromatosis by means of a histological hepatic iron index: a study of 192 cases.

The biochemical hepatic iron index, defined as the ratio of hepatic iron concentration (expressed as micromoles per gram dry weight) to age permits accurate prediction of genetic status in patients with genetic hemochromatosis. However, the hepatic iron concentration is not always available. Therefore a histological hepatic iron index, defined as the ratio of total histological iron score (range = 0 to 60) to age, was evaluated in a total of 192 Australian and French patients with genetic hemochromatosis. These subjects had been classified previously as heterozygotes (n = 18) or homozygotes (n = 174) according to clinical and familial data only. Biochemical hepatic iron index and histological hepatic iron index were well correlated (Spearman's test: rho = 0.75, p < 0.0001). Both were significantly (p < 0.0001) increased in homozygotes (respectively, 6.7 +/- 3.8 [range = 1.2 to 22.6] and 0.62 +/- 0.28 [range = 0.14 to 1.5]) compared with heterozygotes (respectively, 1 +/- 0.4 [range = 0.45 to 1.6] and 0.08 +/- 0.05 [range = 0 to 0.14]). The histological hepatic iron index was less than 0.15 in all heterozygotes and greater than 0.15 in all but two homozygotes. These data show that the age-dependent nature of iron accumulation can also be accommodated by calculating the histological hepatic iron index and that histological study is an accurate means of predicting the genetic status of hemochromatosis patients when hepatic iron concentration is not available.

Adult↗

Familial hemochromatosis: characteristics of the precirrhotic stage in a large kindred.

Ffty asymptomatic members of a kindred with familial hemochromatosis were studied in an effort to clarify some of the physiologic abnormalities present in the pre-cirrhotic or latent stage of the disease. Using excess hepatic iron as a marker for inheritance of hemochromatosis, results of liver biopsies on 31 family members suggest an auto-somal dominant mode of inheritance with incomplete expressivity. In addition to a relationship between alcohol intake and excess liver iron, there was a strong association between the level of alcohol intake and the presence of hepatic fibrosis in those subjects with excess iron stores. Both serum iron and transferrin saturation were significantly higher in family members with iron overload than in those who were not affected. Only transferrin saturation was significantly correlated with the severity of hepatic iron deposition. Studies of glucose tolerance (OGTT, IVITT, glucose clamp studies) demonstrated a defect in carbohydrate metabolism associated with deficient insulin secretion and insulin resistance, both of which were related to the degree of hepatic iron depostion. In this kindred we have found no evidence for a contribution of inheritance to the carbohydrate intolerance of hemochromatosis. Iron overload was not related to activity of hepatic collagen proline hydroxylase or urinary excretion of peptide-bound hydroxyproline. Serum ferritin, previously thought to be a reliable marker of reticuloendothelial iron stores, was normal in 19 of 20 family members with iron overload.

Adolescent↗

The effect of arthritis on the quality of life in hereditary hemochromatosis.

OBJECTIVE: To assess clinical factors affecting the quality of life in patients with hereditary hemochromatosis. METHODS: Fifty consecutive patients with hereditary hemochromatosis completed a self-administered survey (Medical Outcome Survey, MOS-SF36). The effects of cirrhosis, diabetes, and arthritis on physical, social, and general health variables were assessed in 8 subscales including physical, social, emotional, and general health. RESULTS: Multiple linear regression models demonstrated that arthritic patients had impairments in more subcategories (physical functioning, pain and general health perception) than cirrhotic (vitality) and diabetic patients. A multivariate analysis of variance model suggested that arthritis is the strongest single factor affecting quality of life (p = 0.0516). CONCLUSION: Although cirrhosis is the major factor affecting survival, arthritis is a prominent clinical factor affecting quality of life in hemochromatosis.

Analysis of Variance↗

[Long-term efficacy of subcutaneous administration of deferoxamine in patients with secondary hemochromatosis].

A number of studies have shown that regular chelation therapy with deferoxamine is effective in patients with secondary hemochromatosis. However, compliance with these regimen is difficult to obtain in most cases because long-term administration is burdensome. In 3 patients, one each with myelodysplastic syndrome, aplastic anemia and thalassemia intermedia, self-administered subcutaneous one-shot administration of deferoxamine at a dose of 500 mg once or twice daily was carried out over a long period. In all three patients serum ferritin level decreased significantly and the progression of hemochromatosis was prevented. Liver density on computed tomography scan also decreased in one patient. This regimen, in which the patient self-administered deferoxamine subcutaneously one or twice a day is seems to be the most practical method to protect against the progression of hemochromatosis.

Aged↗

[Study of glucagon secretion in patients with hemochromatosis].

Diabetes in idiopathic hemochromatosis has been considered to be secondary to islet cell damage resulting from the iron deposits. Plasma glucagon was measured by immunoassay using the pancreas specific 30-K antiserum, and was found to be normal or slightly elevated during arginine-infusion tests in patients exhibiting both hemochromatosis and pathological glucose tolerance. This suggests that diabetes in hemochromatosis is not due to a lesion resulting from the iron deposits. The two affections appear to be merely associated and are possibly genetically linked.

Diabetes Mellitus↗

[Should we screen for hemochromatosis? Critical analysis of the literature].

This paper focus on the main issues to evaluate before planning public health interventions which may optimise the prevention of hemochromatosis. The main indicators are considered: prevalence, morbidity and mortality of the disease, efficacy of the available treatment, sensitivity, specificity and predictive values of the screening tests; potential benefit of a national screening program in a public health perspective. These are evaluated through a critical appraisal of the clinical, epidemiologic and economic literature on hemochromatosis. The paper emphasizes how individual behavior and preferences become crucial to take into account when well-being subjects will face a population-based screening program. We conclude that further arguments are required before the implementation of a national screening program for hemochromatosis.

Community Health Planning↗

Screening for hemochromatosis: phenotype versus genotype.

Hereditary hemochromatosis is one of the most common inherited disorders among Caucasians of European ancestry. Malregulation of iron absorption from the duodenum eventually leads to iron overload. Although the time required to become iron loaded is variable, it is clear that most homozygotes will eventually become symptomatic. The clinical manifestations can be prevented by prophylactic phlebotomy therapy. Screening young populations is therefore a key to the prevention of disease-related morbidity. Protocols based on the phenotype of high transferrin saturation already exist. The recent identification of a candidate gene for hemochromatosis now allows for a potential genetic screen. Both the phenotypic and the genotypic methods of screening have inherent advantages and disadvantages. Iron-depletion therapy of homozygotes before the development of disease-related morbidity results in normal longevity. National initiatives for hemochromatosis screening will prevent morbidity by identifying and treating young, healthy homozygotes. Healthy, iron-depleted homozygotes should be eligible for health and life insurance at standard rates. Furthermore, healthy homozygotes would make ideal blood donors.

Genetic Testing↗

[Hemochromatosis associated with hereditary spherocytosis].

Hereditary spherocytosis is a chronic hemolytic anemia that very infrequently produces severe iron overload. Only 15 cases of hereditary spherocytosis associated with hemochromatosis have been described previously. It was initially thought that hemochromatosis was the result of the increase of iron stores secondary to chronic hemolysis. Afterwards, it became apparent that iron overload could appear in patients splenectomized. This fact suggested that spherocytosis and idiopathic hemochromatosis could be inherited independently. We describe the case of a 45-year-old man, with known hereditary spherocytosis, splenectomized at 5 years of age, who developed iron overload which affected his heart, liver and pancreas.

Cardiomyopathies↗

Patterns of iron storage in dietary iron overload and idiopathic hemochromatosis.

Bone marrow iron stores rise in proportion to the total body iron store in dietary iron overload. The situation in the genetic disorder of idiopathic hemochromatosis is not as clear. A method for measuring the storage iron concentration chemically on samples of bone marrow obtained by trephine needle biopsy was therefore developed. Its value as a measure of tissue iron stores was established in a preliminary investigation in which specimens of liver, spleen, and bone marrow were obtained at necropsies on 66 South African Negroes among whom dietary iron overload is common. A wide range of nonheme iron concentrations was found, but in each individual there was a highly significant correlation between the concentrations in the three tissues. Nonheme iron concentrations were then determined on trephine bone marrow biopsy specimens from eight Caucasian patients with untreated idiopathic hemochromatosis, and on percutaneous liver biopsy specimens from four of them. The concentrations in the livers were in the anticipated range of 5,000 mug per gram wet weight (2 per cent dry weight). In contrast the geometric mean value for bone marrow iron concentration was 186 mug per gram wet weight, a figure that fell below the fiftieth percentile for marrow iron concentrations in the South African Negroes, whereas the geometric mean liver iron concentration was above the ninetieth percentile. These findings indicate that subjects with idiopathic hemochromatosis whose liver iron stores are grossly increased do not show a comparable rise in bone marrow iron stores.

Adult↗

Initial screening transferrin saturation values, serum ferritin concentrations, and HFE genotypes in Native Americans and whites in the Hemochromatosis and Iron Overload Screening Study.

We compared initial screening transferrin saturation (TfSat) and serum ferritin (SF) phenotypes and HFE C282Y and H63D genotypes of 645 Native American and 43,453 white Hemochromatosis and Iron Overload Screening Study participants who did not report a previous diagnosis of hemochromatosis or iron overload. Elevated measurements were defined as TfSat >50% in men and >45% in women and SF >300 ng/ml in men and >200 ng/ml in women. Mean TfSat was 31% in Native American men and 32% in white men (p = 0.0337) and 25% in Native American women and 27% in white women (p < 0.0001). Mean SF was 153 microg/l in Native American and 151 microg/l in white men (p = 0.8256); mean SF was 55 microg/l in Native American women and 63 microg/l in white women (p = 0.0015). The C282Y allele frequency was 0.0340 in Native Americans and 0.0683 in whites (p < 0.0001). The H63D allele frequency was 0.1150 in Native Americans and 0.1532 in whites (p = 0.0001). We conclude that the screening TfSat and SF phenotypes of Native Americans are similar to those of whites. The allele frequencies of HFE C282Y and H63D are significantly lower in Native Americans than in whites.

Adult↗

Total blood lymphocyte counts in hemochromatosis probands with HFE C282Y homozygosity: relationship to severity of iron overload and HLA-A and -B alleles and haplotypes.

BACKGROUND: It has been reported that some persons with hemochromatosis have low total blood lymphocyte counts, but the reason for this is unknown. METHODS: We measured total blood lymphocyte counts using an automated blood cell counter in 146 hemochromatosis probands (88 men, 58 women) with HFE C282Y homozygosity who were diagnosed in medical care. Univariate and multivariate analyses of total blood lymphocyte counts were evaluated using these variables: sex; age, transferrin saturation, and serum ferritin concentration at diagnosis; units of blood removed by phlebotomy to achieve iron depletion; and human leukocyte antigen (HLA)-A and -B alleles and haplotypes. RESULTS: The mean age at diagnosis was 49 +/- 14 years (range 18 - 80 years) in men and 50 +/- 13 years (range 22-88 years) in women. The correlations of total blood lymphocyte counts with sex, age, transferrin saturation, and serum ferritin concentration at diagnosis, and units of blood removed by phlebotomy to achieve iron depletion were not significant at the 0.05 level. Univariate analyses revealed significant associations between total blood lymphocyte counts and presence of the HLA-A*01, -B*08, and -B*14 alleles, and the A*01-B*08 haplotype. Presence of the A*01 allele, B*08 allele, or A*01-B*08 haplotype were associated with a lower total blood lymphocyte count, whereas presence of the B*14 allele was associated with a greater total blood lymphocyte count. There was an inverse association of total blood lymphocyte count with units of phlebotomy to achieve iron depletion, serum ferritin concentration, and with presence of the A*01-B*08 haplotype. CONCLUSION: We conclude that there is a significant inverse relationship of total blood lymphocyte counts and severity of iron overload in hemochromatosis probands with HFE C282Y homozygosity. The presence of the HLA-A*01 allele or the -B*08 allele was also associated with significantly lower total blood lymphocyte counts, whereas presence of the -B*14 allele was associated with significantly higher total blood lymphocyte counts. In univariate and multivariate analyses, total blood lymphocyte counts were significantly lower in probands with the HLA-A*01-B*08 haplotype than in probands without this haplotype.

Journal Article↗

Is hemochromatosis a risk factor for Alzheimer's disease?

Excess iron accumulation in the brain is a consistent observation in Alzheimer's Disease. Iron affects amyloid precursor protein (AbetaPP) processing and promotes deposition of Abeta. Iron is also among the most potent biological toxins because of its ability to react with oxygen to form reactive oxygen species. Consequently, elucidation of the mechanisms associated with maintaining brain iron homeostasis is fundamentally important to understanding the underlying pathogenesis in AD. The iron overload disorder, Hemochromatosis, is the most common genetic disorder (1:200) so a significant percentage of AD patients can be expected to carry this mutation. Heterozygotes for this mutation also have an increased, but sub-clinical iron burden. Given the high percentage of the population who are at significant risk for iron overload, we propose that the hemochromatosis mutation be considered as a confounding factor when evaluating the contribution of genetic associations with AD and treatment strategies and efficacy. Two recent papers and new evidence presented here that the protein associated with hemochromatosis is expressed on blood vessels, choroid plexus and the ependymal cells in the brain are offered as support for this proposal.

Journal Article↗

Iron overload and prolonged ingestion of iron supplements: clinical features and mutation analysis of hemochromatosis-associated genes in four cases.

We evaluated and treated four white adults (one man, three women) who had iron overload associated with daily ingestion of iron supplements for 7, 15, 35, and 61 years, respectively. We performed HFE mutation analysis to detect C282Y, H63D, and S65C in each patient; in two patients, HFE exons were sequenced. In two patients, direct sequencing was performed to detect coding region mutations of TFR2, HAMP, FPN1, HJV, and ALAS2. Patients 1-4 ingested 153, 547, 1,341, and 4,898 g of inorganic iron as supplements. Patient 1 had hemochromatosis, HFE C282Y homozygosity, and beta-thalassemia minor. Patient 2 had spherocytosis and no HFE coding region mutations. Patient 3 had no anemia, a normal HFE genotype, and no coding region mutations in HAMP, FPN1, HJV, or ALAS2; she was heterozygous for the TFR2 coding region mutation V583I (nt 1,747 G-->A, exon 15). Patient 4 had no anemia and no coding region mutations in HFE, TFR2, HAMP, FPN1, HJV, or ALAS2. Iron removed by phlebotomy was 32.4, 10.4, 15.2, and 4.0 g, respectively. There was a positive correlation of log(10) serum ferritin and the quantity of iron removed by phlebotomy (P = 0.0371). Estimated absorption of iron from supplements in patients 1-4 was 20.9%, 1.9%, 1.1%, and 0.08%. We conclude that the clinical phenotypes and hemochromatosis genotypes of adults who develop iron overload after ingesting iron supplements over long periods are heterogeneous. Therapeutic phlebotomy is feasible and effective, and would prevent complications of iron overload.

Adult↗

Does bilirubin protect against hemochromatosis gene (HFE) related mortality?

Serum bilirubin is an important antioxidant that is found at increased levels in hereditary hemochromatosis patients. We hypothesized that increased levels of serum bilirubin may play a protective role against oxidative stress induced by iron overload in carriers of mutations in the hereditary hemochromatosis gene (HFE). We studied the relation between serum total bilirubin, serum iron levels, the HFE C282Y and H63D mutations, and mortality. The study was conducted in 2,332 randomly selected subjects from the Rotterdam Study, a population-based follow-up study of people aged 55 years or over. Serum bilirubin levels were significantly correlated with serum iron (Pearson's correlation coefficient (r) = 0.4, P < 0.001), transferrin saturation (r = 0.4, P < 0.001), and serum ferritin (r = 0.2, P < 0.05). Carriers of the HFE mutations had higher levels of bilirubin compared to wild-type homozygotes. The relation was the strongest in H63D heterozygotes or homozygotes and C282Y heterozygotes. High levels of serum bilirubin were associated with a 2.8 (95% CI 0.9-8.8) fold reduction in mortality in H63D homozygotes and a 2.2 (1.0-4.7) fold reduction in mortality in C282Y heterozygotes. Taken together, our data suggest that the high levels of the antioxidant bilirubin may counteract the adverse effect of oxidative stress induced by iron overload. This may explain in part the reduced penetrance of the HFE mutations.

Aged↗