Revisiting hereditary hemochromatosis: current concepts and progress

Erastin-induced ferroptosis is a regulator for the growth and function of human pancreatic islet-like cell clusters

Ferroptosis is a newly identified and novel form of cell death, which is characterized by an iron- and reactive oxygen species (ROS)-dependent manner. Potential utility of ferroptotic cell death has been recently proposed for cancer treatment. Meanwhile, ROS generation and apoptosis are inherently consequent to cell apoptosis and dysfunction during islet cell preparation and transplantation. Whether ferroptosis induction is a regulator for cell viability and function in human pancreatic islet-cell clusters (ICCs) derived from pancreatic progenitor cells (PPCs) remains elusive. We thus sought to induce ferroptosis in our established cell culture system of human PPCs/ICCs, examine the effects of ferroptosis on ICCs, and explore the potential regulatory pathways involved. Our results showed that ICCs were prone to the use of ferroptosis-inducing and inhibiting agents under our culture conditions. Erastin, a ferroptosis inducer, was found to trigger ferroptosis in ICCs, without the apparent detection of other types of cell death involved, such as apoptosis and autophagy. In corroboration, the use of ferroptosis inhibitor, ferrostatin-1 (Fer-1), was found to enhance the cell viability of ICCs and prevent them from ferroptosis as well as improve its function. Mechanistically, the erastin-induced ferroptosis in ICCs was probably mediated via activation of JNK/P38/MAPK pathways and upregulation of NOX4 expression. Together, our findings may provide a scientific basis of ferroptosis inhibition as a potential for the amelioration of ICC survival and functionality during islet transplantation in diabetic patients.

Mechanistic basis of the inhibition of SLC11/NRAMP-mediated metal ion transport by bis-isothiourea substituted compounds

In humans, the divalent metal ion transporter-1 (DMT1) mediates the transport of ferrous iron across the apical membrane of enterocytes. Hence, its inhibition could be beneficial for the treatment of iron overload disorders. Here we characterize the interaction of aromatic bis-isothiourea-substituted compounds with human DMT1 and its prokaryotic homologue EcoDMT. Both transporters are inhibited by a common competitive mechanism with potencies in the low micromolar range. The crystal structure of EcoDMT in complex with a brominated derivative defines the binding of the inhibitor to an extracellular pocket of the transporter in direct contact with residues of the metal ion coordination site, thereby interfering with substrate loading and locking the transporter in its outward-facing state. Mutagenesis and structure-activity relationships further support the observed interaction mode and reveal species-dependent differences between pro- and eukaryotic transporters. Together, our data provide the first detailed mechanistic insight into the pharmacology of SLC11/NRAMP transporters.

Hemochromatosis: Hereditary hemochromatosis and HFE gene

Hereditary Hemochromatosis (HH) is an autosomal recessive genetic disease, characterized by an excessively increased absorption of dietary iron. Excess iron can be accumulated because of the lack of an effective excretory mechanism leading to toxic effects. HH is one of the most common genetic disorders in individuals of European descent. Genetic polymorphisms of the HFE gene (rs1800562, rs1799945 and rs1800730) also affect the normal activity of another protein, hepcidin, a negative regulator of iron homeostasis. If left untreated, hereditary hemochromatosis can lead to morbidity and eventually death. Clinical onset hereditary hemochromatosis symptoms occur more frequently in adult men than women, as the monthly loss of iron due to menstruation in women slows down accumulation and the symptoms usually start appearing after menopause. Therapeutic phlebotomy is the primary form of treatment for this disease so far, combined with the use of chelating agents. Orthotopic liver transplantation (OTL) is performed in patients with advanced cirrhosis. In order to prevent the progression of iron accumulation, an early detection may be achieved by genotypic check of the frequent mutations of the HFE. Consequently, initiation of treatment may take place before the development of clinical symptoms, particularly cirrhosis, contributing significantly in achieving normal life expectancy. Therefore, genotypic check is vital in order to prevent the development of this type of hemochromatosis.

Properties of donated red blood cell components from patients with hereditary hemochromatosis

BACKGROUND

Red blood cells (RBCs) contain large amounts of iron, and periodic therapeutic phlebotomy is thus the main treatment for hereditary hemochromatosis (HH). However, the donation of therapeutic phlebotomy products from asymptomatic patients for transfusion purposes remains controversial. In this study, we compared the quality of RBCs obtained from HH patients with those of non-HH RBCs, within the allowed 42-day storage period.

STUDY DESIGN AND METHODS

RBCs were obtained from HH patient donors and random regular blood donors by whole blood collection. RBCs were stored for up to 42 days, according to national regulations and standard blood bank conditions in France. The following variables were assessed: hematologic and biochemical results, RBC membrane and soluble inflammatory markers, and the proinflammatory potential of HH RBC supernatant toward endothelial cells in an in vitro model.

RESULTS

There were no major differences between the two groups in terms of biophysical, biochemical, or soluble immunomodulatory factors. However, we observed small but significant differences in changes in RBC membrane proteins during storage, including increased phosphatidylserine expression and decreased hemolysis in HH compared with normal RBCs. However, there were no differences in terms of bioactivity of soluble immunomodulatory factors in the RBC supernatant during storage between HH and control donors, as determined by their effects on endothelial cells in vitro.

CONCLUSIONS

These in vitro studies suggest that RBCs from HH patients appear, while exhibiting subtle differences, to be suitable for transfusion purposes according to currently accepted criteria.

Population-based analysis of the frequency of HFE gene polymorphisms: Correlation with the susceptibility to develop hereditary hemochromatosis

Hereditary hemochromatosis (HH) is an autosomal recessive genetic disease, characterized by increased dietary iron absorption. Due to the absence of an effective excretory mechanism, the excess iron in the body may accumulate resulting in toxic effects. The HFE gene also affects the activity of hepcidin, a hormone which acts as a negative regulator of iron metabolism. In this study, we performed a population-based analysis of the distribution of three hemochromatosis-related polymorphisms in the HFE gene (rs1800562, rs1799945 and rs1800730). DNA from 1,446 non‑related individuals of Greek ethnicity was collected and analyzed, either from whole blood or buccal swabs. The frequency distribution of these HFE gene polymorphisms was then determined. The results revealed that in our Greek population cohort (gr) the frequencies of each polymorphism were as follows: rs1800562: GG (wild‑type)=97.0%, GA=1.5%, AA=1.5%; rs1799945: CC (wild‑type)=74.4%, CG=23.4%, GG=2.2%; rs1800730: AA (wild‑type)=98.1%, AT=1.5% and TT=0.4%. No association between the HFE polymorphisms rs1800562, rs1799945 and rs1800730 and gender could be established. As regards the rs1800562 polymorphism, the A allele (mutant) was ~1.8‑fold more frequent in the European population (eur) than in the Greek population [(gr)=2,3%<(eur)=4%]. As for the rs1799945 polymorphism, the G allele (mutant) was 1.2‑fold more frequent in the European population than in the Greek population [(gr)=13,9%<(eur)=17%]. As regards the rs1800730 polymorphism, the T allele (mutant) was ~1.7‑fold more frequent in the European population than in the Greek population [(gr)=1.2%<(eur)=2%]. However, these pathogenic mutations were found more frequently in the Greek population compared to the global population (gl) [rs1800562: (gl)=1%<(gr)=2,3%; rs1799945: (gl)=7%<(gr)=13,9%; rs1800730: (gl)=<1%<(gr)=1.2%]. This suggests that the Greek population may differ genetically from the northern European population, due to influences from neighboring Asian and African populations. These findings also suggest that there is no gender-associated inheritance of these polymorphisms, and gender-specific symptoms appear as a result of independent biological processes. Thus, the early detection of the tendency towards iron accumulation may be achieved by the genotypic analysis of the polymorphisms that may contribute to the development of the hemochromatosis.

Effects of Iron Overload on the Activity of Na,K-ATPase and Lipid Profile of the Human Erythrocyte Membrane

Iron is an essential chemical element for human life. However, in some pathological conditions, such as hereditary hemochromatosis type 1 (HH1), iron overload induces the production of reactive oxygen species that may lead to lipid peroxidation and a change in the plasma-membrane lipid profile. In this study, we investigated whether iron overload interferes with the Na,K-ATPase activity of the plasma membrane by studying erythrocytes that were obtained from the whole blood of patients suffering from iron overload. Additionally, we treated erythrocytes of normal subjects with 0.8 mM H₂O₂ and 1 μM FeCl₃ for 24 h. We then analyzed the lipid profile, lipid peroxidation and Na,K-ATPase activity of plasma membranes derived from these cells. Iron overload was more frequent in men (87.5%) than in women and was associated with an increase (446%) in lipid peroxidation, as indicated by the amount of the thiobarbituric acid reactive substances (TBARS) and an increase (327%) in the Na,K-ATPase activity in the plasma membrane of erythrocytes. Erythrocytes treated with 1 μM FeCl₃ for 24 h showed an increase (132%) in the Na,K-ATPase activity but no change in the TBARS levels. Iron treatment also decreased the cholesterol and phospholipid content of the erythrocyte membranes and similar decreases were observed in iron overload patients. In contrast, erythrocytes treated with 0.8 mM H₂O₂ for 24 h showed no change in the measured parameters. These results indicate that erythrocytes from patients with iron overload exhibit higher Na,K-ATPase activity compared with normal subjects and that this effect is specifically associated with altered iron levels.

HFE-associated hereditary hemochromatosis: overview of genetics and clinical implications for nurse practitioners in primary care settings

PURPOSE

HFE-hemochromatosis is one of the most common genetic disorders in the United States among Caucasians of Northern European ancestry. The purpose of this article is to discuss HFE-associated hereditary hemochromatosis (HH), including the genetics, pathophysiology, phenotype and genotype, diagnostics, and management utilizing a case-based format as an exemplar.

DATA SOURCES

Online genetic resources; professional guidelines; review; and scientific articles.

CONCLUSION

HFE-HH is an autosomal recessive disorder and two major genes C282Y and H63D are associated with HH (iron overload) susceptibility particularly C282Y/C282Y mutations. It has a variable penetrance and expression. Individuals who develop iron overload may develop broad symptoms, including joint discomfort, fatigue, decreased libido, and abdominal pain; and if left untreated, HFE-HH has the potential of developing end-organ disease including liver fibrosis, cirrhosis, and cancer; cardiac arrhythmias or heart failure; and diabetes. Suspicion of the disorder begins with personal and family history, transferrin saturation, and ferritin levels, and if high, genotyping to confirm the disorder. Management consists of correcting iron overload to prevent/delay end-organ damage often consisting of intermittent phlebotomy.

IMPLICATIONS FOR PRACTICE

Knowledge of HFE-HH is essential so that nurse practitioners can identify individuals at risk and to provide appropriate management of care and referral.

Erythrocytapheresis compared with whole blood phlebotomy for the treatment of hereditary haemochromatosis

BACKGROUND

Hereditary haemochromatosis may result in severe organ damage which can be prevented by therapy. We studied the possible advantages and disadvantages of erythrocytapheresis as compared with phlebotomy in patients with hereditary haemochromatosis.

MATERIALS AND METHODS

In a prospective, randomised, open-label study, patients with hereditary haemochromatosis were randomised to bi-weekly apheresis or weekly whole blood phlebotomy. Primary end-points were decrease in ferritin levels and transferrin saturation. Secondary endpoints were decrease in haemoglobin levels, discomfort during the therapeutic procedure, costs and technicians' working time.

RESULTS

Sixty-two patients were included. Thirty patients were randomised to apheresis and 32 to whole blood phlebotomy. Initially, ferritin levels declined more rapidly in the apheresis group, and the difference became statistically highly significant at 11 weeks; however, time to normalisation of ferritin level was equal in the two groups. We observed no significant differences in decline of transferrin saturation, haemoglobin levels or discomfort. The mean cumulative technician time consumption until the ferritin level reached 50 μg/L was longer in the apheresis group, but the difference was not statistically significant. The cumulative costs for materials until achievement of the desired ferritin levels were three-fold higher in the apheresis group.

CONCLUSION

Treatment of hereditary haemochromatosis with erythrocytapheresis instead of whole blood phlebotomy results in a more rapid initial decline in ferritin levels and a reduced number of procedures per patient, but not in earlier achievement of target ferritin level. The frequency of discomfort was equally low with the two methods. The costs and, probably, technician time consumption were higher in the apheresis group.

Iron metabolism: current facts and future directions

Iron metabolism has been intensively examined over the last decade and there are many new players in this field which are worth to be introduced. Since its discovery many studies confirmed role of liver hormone hepcidin as key regulator of iron metabolism and pointed out liver as the central organ of system iron homeostasis. Liver cells receive multiple signals related to iron balance and respond by transcriptional regulation of hepcidin expression. This liver hormone is negative regulator of iron metabolism that represses iron efflux from macrophages, hepatocytes and enterocytes by its binding to iron export protein ferroportin. Ferroportin degradation leads to cellular iron retention and decreased iron availability. At level of a cell IRE/IRP (iron responsive elements/iron responsive proteins) system allows tight regulation of iron assimilation that prevents an excess of free intracellular iron which could lead to oxidative stress and damage of DNA, proteins and lipid membranes by ROS (reactive oxygen species). At the same time IRE/IRP system provides sufficient iron in order to meet the metabolic needs.

Recently a significant progress in understanding of iron metabolism has been made and new molecular participants have been characterized. Article gives an overview of the current understanding of iron metabolism: absorption, distribution, cellular uptake, release, and storage. We also discuss mechanisms underlying systemic and cellular iron regulation with emphasis on central regulatory hormone hepcidin.

Effect of phlebotomy on lipid metabolism in subjects with hereditary hemochromatosis

Genetic predisposition to hereditary hemochromatosis (HH) is associated with primary hypertriglyceridemia (HTG). If iron overload influences the development of HTG, the management of these patients could be different. However, the metabolic syndrome in primary HTG is frequent; and it could partially confuse the association. The objective was to determine whether periodic bloodletting could decrease triglyceride concentrations in subjects with HH and iron overload. We retrospectively studied 155 genetically defined HH patients (C282Y homozygotes and compound heterozygotes C282Y/H63D) with iron overload and under periodic therapeutic phlebotomy. Hypertriglyceridemia (triglycerides ≥150 mg/dL) was present in 49 subjects at baseline (31.6%). Phlebotomies significantly decreased triglycerides, especially in subjects with basal HTG (from 287 mg/dL at baseline to 133 mg/dL after phlebotomies, P < .001). Blood glucose and total cholesterol did not change with phlebotomies. The triglyceride-lowering effect was obtained until ferritin concentration decreased to less than 200 μg/L and transferrin saturation to less than 40%. The triglyceride-lowering effect was obtained for glucose levels both less than and greater than 100 mg/dL. In summary, HH subjects frequently have HTG that improves after therapeutic phlebotomy, independently of basal blood glucose. Our results suggest that therapeutic phlebotomy could be a useful therapeutic approach in patients with HTG and iron overload.

Hereditary hemochromatosis: laboratory evaluation

The condition of hereditary hemochromatosis (HH) is caused by gene-dependent protein abnormalities involved in iron absorption, storage, or modulation of iron; these abnormalities result in iron overload. The clinical laboratory plays a significant role in case finding, diagnostic validation, and monitoring HH therapy. Elevated serum iron, transferrin saturation, and ferritin suggest HH, but results can also indicate other forms of hepatocyte injury such as alcoholic or viral hepatitis, or other inflammatory disorders involving the liver. In the context of elevated serum iron, transferrin saturation, and ferritin, and after ruling out secondary causes of iron overload, HFE gene evaluation is the preferred test to confirm the diagnosis of HH. However, 5% to 15% of patients with phenotypic HH do not have HFE gene mutations. In these cases, MRI evaluation or liver biopsy with iron quantification is indicated. The clinical role of hepcidin, the iron modulating protein, is undetermined at this time. Because hepcidin also plays a key role in antimicrobial and inflammatory activities, interpretation of hepcidin serum or urine concentration will require thorough understanding of its complex role in iron regulation.

MEDWISE: an innovative public health information system infrastructure

In this paper, we present MedWise, a high level design of a medical information infrastructure, and its architecture. The proposed system offers a comprehensive, modular, robust and extensible infrastructure to be used in public health care systems. The system gathers reliable and evidence based health data, which it then classifies, interprets and stores into a particular database. It creates a healthcare ecosystem that aids the medical community by providing for less error prone diagnoses and treatment of diseases. This system will be standards-compliant; therefore it would be complementary to the existing healthcare and clinical information systems. The key objective of the proposed system is to provide as much medical historical and miscellaneous data as possible about the patients with minimal consultation, thus allowing physicians to easily access Patients' Ancillary Data (PAD) such as hereditary, residential, travel, custom, meteorological, biographical and demographical data before the consultation. In addition, the system can help to diminish problems and misdiagnosis situations caused by language barriers-disorders and misinformation. MedWise can assist physicians to shorten time for diagnosis and consultations, therefore dramatically improving quality and quantity of the physical examinations of patients. Furthermore, since it intends to supply a significant amount of data, it may be used to improve skills of students in medical education.

Screening for thyroid disease: defining high-risk populations

The pros and cons of population screening for thyroid disease have been hotly debated over the past several decades. This article addresses the issue from the point of view of the potential benefit of screening, that is, disease detection. Earlier diagnoses of hypothyroidism, hyperthyroidism, thyroid nodules, thyroid cancer and so on, with implementation of the indicated diagnostic and therapeutic interventions, avoid the adverse consequences of unrecognized and untreated progressive disease. Arguments against screening and case-finding often focus on cost considerations. To achieve the greatest yield at the lowest cost, our emphasis is on vulnerable populations with associated risk factors, and special situations such as pregnancy.

Impact of gene patents and licensing practices on access to genetic testing for hereditary hemochromatosis

Hereditary hemochromatosis is an iron metabolism disorder that leads to excess iron buildup, especially in the heart, liver, and pancreas. Mutations in the HFE gene are the single most common cause of hereditary hemochromatosis, which can be treated effectively if diagnosed early. Patents cover the HFE gene, related proteins, screening methods, and testing kits. Most initial testing for hereditary hemochromatosis is biochemical, but HFE deoxyribonucleic acid testing or genotyping is used to confirm a diagnosis of inherited hemochromatosis. Concerns over patents covering HFE testing emerged in 2002, when scholars argued that exclusive licensing and the patent-enabled sole provider model then in place led to high prices and limited access. Critics of the sole provider model noted that the test was available at multiple laboratories before the enforcement of patents. By 2007, however, Bio-Rad Limited, acquired the key intellectual property and sublicensed it widely. In part because of broad, nonexclusive licensing, there are now multiple providers and testing technologies, and research continues. This case study illustrates how both changes in intellectual property ownership and evolving clinical utility of HFE genetic testing in the last decade have effected the licensing of patents and availability of genetic testing.

Phenotypic characteristics and diagnoses of patients referred to an iron overload clinic

BACKGROUND

There are limited data on the phenotypic differences between patients with hereditary hemochromatosis (HH) and other forms of iron overload.

AIMS

To describe and compare patients suspected of having iron overload disease.

METHODS

Patients were evaluated at a university iron overload clinic over a 5-year period. Biochemical and clinical profiles of patients with HH and non-HH causes of suspected iron overload were retrospectively compared.

RESULTS

A total of 270 patients were evaluated during the enrollment period, and 137 (51%) were diagnosed with HH. The most common reasons for referral were elevated serum iron markers (155 patients), followed by positive family history (40 patients), and known HH (75 patients). In patients without HH referred for suspected iron overload, the most common diagnoses were nonalcoholic fatty liver disease (NAFLD) (24%), chronic hepatitis C infection (14%), and alcohol related liver disease (9%). Of the patients with HH, 108 were C282Y homozygotes, 20 were compound heterozygotes (C282Y/H63D), and nine had neither mutation. The following clinical characteristics were significantly different (p < 0.05) between patients with HH and all other referred patients: arthralgia (42 vs. 16%) and decreased libido (11 vs. 4%). There was a non-significant trend towards increased fatigue (44 vs. 33%), diabetes (10 vs. 6%), impotence (8 vs. 4%), and hypothyroidism (10 vs. 6%) in the HH group.

CONCLUSIONS

(1) A large proportion of patients referred for suspected iron overload have diagnoses other than HH. (2) NAFLD, chronic hepatitis C, and chronic alcohol use were the most common alternative diagnoses. (3) Arthralgia and fatigue are the most common symptoms among patients with HH.

Serum ferritin is a major determinant of lipid phenotype in familial combined hyperlipidemia and familial hypertriglyceridemia

Familial combined hyperlipidemia (FCH) and familial hypertriglyceridemia (FHTG) share pathogenic mechanisms and a high interaction with components of the metabolic syndrome. The metabolic syndrome associates increased serum ferritin concentration and high cardiovascular risk. The objective was to describe the frequency of iron overload and the relationship between serum ferritin and the phenotype in patients with FCH and FHTG. The study was composed of 211 consecutive unrelated patients aged at least 18 years with primary hypertriglyceridemia, 149 with FCH, and 62 with FHTG. The prevalence of the metabolic syndrome and hyperferritinemia was very high in both hypertriglyceridemic groups (51.7% and 20.1% in FCH and 62.9% and 16.1% in FHTG, respectively), without significant statistical differences between them. Serum ferritin concentration did not show any significant association with the number of metabolic syndrome criteria. Subjects in the highest tertile of ferritin concentration (ferritin >200 mug/L) presented higher concentrations of triglycerides and liver enzymes than subjects in the first tertile of ferritin concentration (ferritin <90 mug/L). The highest positive correlation coefficient for triglycerides was found with ferritin in FCH and in FHTG subjects (R = 0.317 [P < .001] when combined). Ferritin was also the covariate that showed the highest independent association with triglycerides in FCH and FHTG. In contrast, ferritin was not associated with carotid intima-media thickness. In summary, serum ferritin is commonly increased in FCH and in FHTG, it is not related with the presence of metabolic syndrome, and it is highly correlated with liver enzymes.

Mutations in HFE causing hemochromatosis are associated with primary hypertriglyceridemia

CONTEXT

Most cases of primary hypertriglyceridemia (HTG) are caused by the interaction of unknown polygenes and environmental factors. Elevated iron storage is associated with metabolic syndrome, diabetes, and obesity, and all of them are associated with HTG.

OBJECTIVE

The aim of the study was to analyze whether HFE mutations causing hereditary hemochromatosis (HH) are associated with primary HTG.

DESIGN

Genetic predisposition to HH was analyzed in a case-control study.

SETTING

The study was conducted at University Hospital Lipid Clinic.

PARTICIPANTS

We studied two groups: 1) the HTG group, composed of 208 patients; and 2) the control group, composed of 215 normolipemic subjects and 161 familial hypercholesterolemia patients.

INTERVENTION

Two HFE mutations (C282Y and H63D) were analyzed.

MAIN OUTCOME MEASURE

We measured HH genetic predisposition difference between groups.

RESULTS

HH genetic predisposition was 5.9 and 4.4 times higher in the HTG group than in the normolipemic (P = 0.02) and FH (P = 0.05) subjects, respectively. There were 35 cases (16.8%) of iron overload in the primary HTG group, 14 (6.5%) and nine (5.6%) in the normolipidemic and FH groups, respectively. A higher HH genetic predisposition and a different prevalence of iron overload in subjects with HH genetic predisposition among groups contributed to this higher prevalence. None of the four cases with the HFE genotype associated with high risk of HH in the control groups presented iron overload; however, in eight of 11 subjects (72.7%) with primary HTG and HH genetic predisposition, the iron overload was present.

CONCLUSION

Mutations in HFE gene, favoring iron overload and causing HH, could play an important role in the development of several phenotypes of primary HTG.

Twenty questions in genetic medicine--an assessment of World Wide Web databases for genetics information at the point of care

PURPOSE

The aim of this article was to determine the accuracy and efficiency of World Wide Web ("Web") resources to help nongeneticists answer four clinical questions about each of five common genetic conditions.

METHODS

Correct answers were established by literature review. Two open-access genetics resources and seven general subscription resources were reviewed. Scoring criteria were established to define complete, partial, vague, inconsistent, not found, and wrong answers. The main outcome measures were number of answers found, accuracy, and completeness of answers. Efficiency (time per answer found) was a secondary measure.

RESULTS

Overall, the databases contained complete answers 33.3% of the time but contained no information as frequently (33.9%). The best database had complete answers 70% of the time, whereas the worst contained no complete answers. Five of the seven subscription databases had a total of eight wrong answers. The other two subscription databases and the two open-access genetics databases had no wrong answers. Search time ranged from 3.2 to 18.3 minutes per complete answer.

CONCLUSIONS

Nongeneticist providers do not have a Web resource that is accessible, accurate, and efficient to answer genetic questions that might arise in practice.

All patients with 'idiopathic' hypopituitarism should be screened for hemochromatosis

Hypopituitarism usually occurs as the result of a pituitary tumour or as a consequence of its treatment. If, however, pituitary imaging is negative then an alternative diagnosis should be sought. Patients are often diagnosed as having idiopathic hypopituitarism when imaging is normal. Our objective is to highlight the importance of screening for hemochromatosis in patients with presumed 'idiopathic' hypopituitarism. Our patients presented initially with biochemical hypopituitarism and, after initial investigation and normal imaging, were labelled as having idiopathic disease. They subsequently developed iron overload in cardiac and hepatic tissue respectively requiring regular venesection to deplete body stores. Genetic analysis revealed homozygosity for the C282Y mutation in our first patient thus explaining his more severe iron overload whereas our second case was a heterozygote for the same mutation, with iron overload confirmed on liver biopsy. We recommend that iron studies are performed in all patients who present with hypopituitarism and normal pituitary imaging. This may lead to reversal of the hypopituitarism and avoid development of any systemic consequences of hemochromatosis.

A decision analysis model for diagnostic strategies using DNA testing for hereditary haemochromatosis in at risk populations

BACKGROUND

New techniques for diagnosing hereditary haemochromatosis (HHC) have become available alongside traditional tests such as liver biopsy and serum iron studies.

AIM

To evaluate DNA tests in people suspected of having haemochromatosis at clinical presentation compared to liver biopsy, and in family members of those diagnosed with haemochromatosis compared to phenotypic iron studies in UK.

METHODS

Decision analytic models were constructed to compare the costs and consequences of the diagnostic strategies for a hypothetical cohort of people with suspected haemochromatosis. For each strategy, the number of cases of haemochromatosis identified and treated and the resources used were estimated.

RESULTS

For diagnostic strategies in people suspected clinically of having haemochromatosis, the DNA strategy is cost saving compared to liver biopsy (cost saved per case detected, 123 pounds) and continues to be so across all ranges of parameters. For family testing, the DNA strategy is cost saving for the offspring of the proband but not for siblings. If the DNA test cost were to reduce by 40% to 60 pounds or, if in the phenotypic model, those with initially normal iron indices were retested twice instead of once, the DNA strategy would be the cheaper one.

CONCLUSION

Diagnostic strategies involving DNA testing are likely to be cost saving in clinical cases with iron overload and in the offspring of index cases. This study supports the UK guideline recommendations for the use of DNA testing in UK.

Body iron metabolism and pathophysiology of iron overload

Iron is an essential metal for the body, while excess iron accumulation causes organ dysfunction through the production of reactive oxygen species. There is a sophisticated balance of body iron metabolism of storage and transport, which is regulated by several factors including the newly identified peptide hepcidin. As there is no passive excretory mechanism of iron, iron is easily accumulated when exogenous iron is loaded by hereditary factors, repeated transfusions, and other diseased conditions. The free irons, non-transferrin-bound iron, and labile plasma iron in the circulation, and the labile iron pool within the cells, are responsible for iron toxicity. The characteristic features of advanced iron overload are failure of vital organs such as liver and heart in addition to endocrine dysfunctions. For the estimation of body iron, there are direct and indirect methods available. Serum ferritin is the most convenient and widely available modality, even though its specificity is sometimes problematic. Recently, new physical detection methods using magnetic resonance imaging and superconducting quantum interference devices have become available to estimate iron concentration in liver and myocardium. The widely used application of iron chelators with high compliance will resolve the problems of organ dysfunction by excess iron and improve patient outcomes.

Iron overload syndromes and the liver

Iron can accumulate in the liver in a variety of conditions, including congenital, systemic iron-loading conditions (hereditary hemochromatosis), conditions associated with systemic macrophage iron accumulation (transfusions, hemolytic conditions, anemia of chronic disease, etc), in some hepatitidies (hepatitis C, alcoholic liver disease, porphyria cutanea tarda), and liver-specific iron accumulation of uncertain pathogenesis in cirrhosis. The anatomic pathologist will be faced with the task of determining whether iron accumulation in the liver is significant and, if so, the nature of the disease that lead to the accumulation (ie diagnosis). The tools available to the pathologist include (most importantly) histologic examination with iron stain, quantitative iron analysis, clinical history, laboratory iron tests (serum iron and iron-binding capacity, serum ferritin) and germline genetic analysis for mutations in genes known to be associated with hemochromatosis (HFE, ferroportin, hepcidin, hemojuvelin, transferrin receptor-2). This article provides an overview of the above.