Haemochromatosis in children: A national retrospective cohort promoted by the A.I.E.O.P. (Associazione Italiana Emato-Oncologia Pediatrica) study group.

Haemochromatosis (HC) encompasses a range of genetic disorders. HFE-HC is by far the most common in adults, while non-HFE types are rare due to mutations of HJV, HAMP, TFR2 and gain-of-function mutations of SLC40A1. HC is often unknown to paediatricians as it is usually asymptomatic in childhood. We report clinical and biochemical data from 24 paediatric cases of HC (10 cases of HFE-, 5 TFR2-, 9 HJV-HC), with a median follow-up of 9.6 years. Unlike in the adult population, non-HFE-HC constitutes 58% (14/24) of the population in our series. Transferrin saturation was significantly higher in TFR2- and HJV-HC compared to HFE-HC, and serum ferritin and LIC were higher in HJV-HC compared to TFR2- and HFE-HC. Most HFE-HC subjects had relatively low ferritin and LIC at the time of diagnosis, so therapy could be postponed for most of them after the age of 18. Our results confirm that HJV-HC is a severe form already in childhood, emphasizing the importance of early diagnosis and treatment to avoid the development of organ damage and reduce morbidity and mortality. Although phlebotomies were tolerated by most patients, oral iron chelators could be a valid option in early-onset HC.

Haemochromatosis patients' research priorities: Towards an improved quality of life.

BACKGROUND: Chronic diseases are associated with a range of functional and psychosocial consequences that can adversely affect patients' quality of life (QoL). Haemochromatosis (HC) is a genetically heterogeneous disorder characterized by chronic iron overload that can ultimately lead to multiple organ dysfunction. Clinical diagnosis remains challenging due to the nonspecificity of symptoms and a lack of confirmatory genotyping in a substantial proportion of patients. Illness perception among HC patients has not been extensively investigated, lacking relevant information on how to improve their QoL. METHODS: We present the results of the first worldwide survey conducted in nearly 1500 HC respondents, in which we collected essential demographic information and identified the aspects that concern HC patients the most. RESULTS: Out of all the participants, 45.3% (n = 676) voiced their concern about physical and psychological consequences such as HC-related arthropathies, which can ultimately affect their social functioning. A similar proportion of patients (n = 635, 42.5%) also consider that better-informed doctors are key for improved HC disease management. Taking a patient-centred approach, we expose differences in patients' disease perspective by social and economic influences. CONCLUSIONS: We identify potential targets to improve patients' health-related QoL and reflect on strategic measures to foster gender equity in access to health resources. Finally, we make a call for a highly coordinated effort across a range of public policy areas to empower participants in the HC research process and design. PATIENT OR PUBLIC CONTRIBUTION: Nearly 1500 patients with hereditary HC responded to an anonymized online survey in which research and clinical priorities were addressed regarding this chronic and rare disease.

Indices of iron homeostasis in asymptomatic subjects with HFE mutations and moderate ferritin elevation during iron removal treatment.

We analysed iron biomarkers and their relationships in 30 subjects with HFE mutations and moderate hyperferritinaemia undergoing iron removal at our blood donation centre. Body mass index (BMI) and liver enzymes were assessed. Serum iron (SI), ferritin, transferrin saturation (TSAT), hepcidin and non-transferrin bound iron (NTBI) were measured serially. Seventeen subjects had p.C282Y/p.C282Y, nine p.C282Y/p.H63D, four p.H63D/p.H63D. Median age (p = 0.582), BMI (p = 0.500) and ferritin (p = 0.089) were comparable. At baseline, 12/17 p.C282Y/p.C282Y and 2/9 p.C282Y/p.H63D had measurable NTBI (p = 0.003). The p.C282Y/p.C282Y had higher TSAT (p < 0.001), lower hepcidin (p = 0.031) and hepcidin/ferritin ratio (p = 0.073). After treatment, iron indices were similar among groups, except TSAT (higher in p.C282Y/p.C282Y; p = 0.06). Strong relationships were observed between ferritin and TSAT (R = 0.71), NTBI and TSAT (R = 0.61), NTBI and SI (R = 0.54) in p.C282Y/p.C282Y. Hepcidin correlated weakly with ferritin in p.C282Y/p.C282Y (R = 0.37) but strongly in p.C282Y/p.H63D (R = 0.66) and p.H63D/p.H63D (R = 0.72), while relationships with TSAT were weak (R = 0.27), moderate (R = 0.55) and strong (R = 0.61), respectively. Low penetrance p.C282Y/p.C282Y phenotype displays hepcidin dysregulation and biochemical risk for iron toxicity.

Patient-reported outcomes and their relation with iron parameters in HFE haemochromatosis during maintenance therapy: A prospective cohort study.

BACKGROUND & AIMS: The standard of care for haemochromatosis is regular phlebotomy in order to maintain low ferritin levels. Many patients report fatigue or joint pain despite serum ferritin within the therapeutic targets. We evaluated Patient-Reported Outcomes, and their relation with iron parameters, in C282Y homozygous patients undergoing maintenance phlebotomy. METHODS: Patients were prospectively enrolled in a French referral care centre. At each phlebotomy, patients completed a numeric fatigue scale, a joint pain questionnaire and SF-36 Mental Component Score (MCS) and Physical Component Score (PCS). Haemoglobin, iron, TS and ferritin were collected concomitantly. RESULTS: About 701 visits were performed in 259 patients. The median fatigue score was 3/10; 171 (66%) patients reported joint pain. Age and worsening of joint pain were associated with fatigue (p < .0001 for both). Female gender (p < .037), age (p < .003), and a decrease of TS (p = .050) were associated with joint pain. Main features associated with PCS <50 were worsening of joint pain and age (p < .001 for both) and TS <20% (p < .02). CONCLUSIONS: Fatigue was independent from iron parameters. The main factor impacting quality of life was joint pain, which was more severe in patients with low TS values. Then, a more precise monitoring of TS should be proposed during haemochromatosis maintenance therapy; while less stringent monitoring of serum ferritin levels could be tested.

Brain iron deposition and movement disorders in hereditary haemochromatosis without liver failure: A cross-sectional study.

BACKGROUND AND PURPOSE: Hereditary haemochromatosis (HH) is the most common inherited disorder of systemic iron excess in Northern Europeans. Emerging evidence indicates that brain iron overload occurs in HH. Despite this observation, there is a paucity of literature regarding central neurological manifestations, in particular movement disorders, in HH. The current study documents deep gray matter (DGM) nuclei iron deposition, movement disorders, and clinicoradiological correlations in HH without liver failure. METHODS: This is a cross-sectional study. Consecutive subjects with HFE-haemochromatosis without liver disease were recruited from an outpatient gastroenterology clinic. Age- and sex-matched healthy controls (HCs) were enrolled. Iron content in individual DGM nuclei was measured as mean susceptibility on magnetic resonance imaging using quantitative susceptibility mapping-based regions of interest analysis. Occurrence and phenotype of movement disorders were documented and correlated with patterns of DGM nuclei iron deposition in subjects with HH. RESULTS: Fifty-two subjects with HH and 47 HCs were recruited. High magnetic susceptibility was demonstrated in several DGM nuclei in all HH subjects compared to HCs. Thirty-five subjects with HH had movement disorders. Magnetic susceptibility in specific DGM nuclei correlated with individual movement disorder phenotypes. Serum ferritin, phlebotomy frequency, and duration were poor predictors of brain iron deposition. CONCLUSIONS: Abnormal brain iron deposition can be demonstrated on imaging in all subjects with HH without liver failure. A significant proportion of these subjects manifest movement disorders. Peripheral iron measurements appear not to correlate with brain iron deposition. Therefore, routine neurological examination and quantitative brain iron imaging are recommended in all subjects with HH.

Iron accumulation is associated with periodontal destruction in a mouse model of HFE-related haemochromatosis.

OBJECTIVE: To investigate the effect of Hfe gene mutation on the distribution of iron and periodontal bone loss in periodontal tissues. BACKGROUND DATA: It remains unclear how tissue iron loading affects the periodontium architectures in a genetic animal model of hereditary haemochromatosis (HH). METHODS: Male C57BL/6 Hfe -/- (8 weeks old) and wild-type (WT) mice were utilized to examine the iron distribution in periodontal tissues, as well as periodontal tissues changes using micro-computed tomography and histomorphometric analysis. Furthermore, tissue inflammatory mediators, bone markers and periodontal pathogens were carried out in PFA-fixed paraffin-embedded tissues using ELISA, RT-qPCR and genomic DNA qPCR, respectively. RESULTS: Excessive iron deposition was found in the periodontal ligament, gingiva and alveolar bone in Hfe -/- mice relative to their WT counterparts. This, in turn, was associated with significant periodontal bone loss, increased cemento-enamel junction-alveolar bone crest distance and decreased expression of molecules involved in bone development and turnover. Furthermore, the pro-inflammatory cytokine - interleukin 6 and periodontal bacteria - Campylobacter rectus were significantly increased in Hfe -/- mice compared with WT controls. CONCLUSION: Our results suggest that the iron loading in a mouse model of HH decreases alveolar bone formation and leads to alterations in the inflammatory state in the periodontium. Periodontal health should be assessed during the clinical assessment of HFE-HH patients.

Physiological and pathophysiological mechanisms of hepcidin regulation: clinical implications for iron disorders.

The discovery of hepcidin has provided a solid foundation for understanding the mechanisms of systemic iron homeostasis and the aetiologies of iron disorders. Hepcidin assures the balance of circulating and stored iron levels for multiple physiological processes including oxygen transport and erythropoiesis, while limiting the toxicity of excess iron. The liver is the major site where regulatory signals from iron, erythropoietic drive and inflammation are integrated to control hepcidin production. Pathologically, hepcidin dysregulation by genetic inactivation, ineffective erythropoiesis, or inflammation leads to diseases of iron deficiency or overload such as iron-refractory iron-deficiency anaemia, anaemia of inflammation, iron-loading anaemias and hereditary haemochromatosis. In the present review, we discuss recent insights into the molecular mechanisms governing hepcidin regulation, how these pathways are disrupted in iron disorders, and how this knowledge is being used to develop novel diagnostic and therapeutic strategies.

Ankle arthritis - an important signpost in rheumatologic practice.

Ankle arthritis is a useful clinical signpost to differential diagnosis in rheumatic disease. Biomechanical features and differences in cartilage physiology compared with the knee may confer protection of the ankle joint from factors predisposing to certain arthritides. The prevalence of ankle OA is low, and usually secondary to trauma. Primary OA of the ankle should be investigated for underlying causes, especially haemochromatosis. New presentations of inflammatory mono/oligo arthritis involving the ankle are more likely due to undifferentiated arthritis or spondyloarthritis than RA, and gout over CPPD. The ankle is often involved in bacterial and viral causes of septic arthritis, especially bacterial, chikungunya and HIV infection, but rarely tuberculosis. Periarticular hind foot swelling can be confused with ankle arthritis, exemplified by Lofgren's syndrome and hypertrophic osteoarthropathy where swelling is due to subcutaneous oedema and osteitis respectively, and the ankle joint is rarely involved.

Clinical characteristics of endocrinopathies in Chinese patients with hereditary haemochromatosis.

AIMS: Hereditary haemochromatosis (HH) is a genetic disorder characterised by systemic iron overload and can lead to end-organ failure. However, very few data on this disorder, especially those on endocrine gland involvement in Chinese populations, are currently available. This study aimed to analyse the clinical features of endocrinopathies in patients with HH to generate concern among endocrinologists and improve the management of this disorder. MATERIALS AND METHODS: Chinese patients with HH-related endocrine dysfunction were enrolled at Peking Union Medical College Hospital from January 2010 to December 2018. All clinical data were analysed and summarised. RESULTS: A total of six patients were enrolled in this study, comprising five men and one woman; the average age was 36.5 ± 13.3 years. Mean serum ferritin concentration was 4508.8 ± 1074.3 ng/ml, and median transferrin saturation was 97.9% (96.6%-110.0%). Endocrine gland involvement associated with HH included the pancreas (5/6 patients), the adenohypophysis (5/6 patients) and the bones (1/6 patients); secondary endocrinopathies consisted of diabetes mellitus, hypogonadism, adrenal insufficiency and osteoporosis. Based on phlebotomy and iron chelation therapy, five patients were treated with exogenous insulin preparations, and three patients were treated with exogenous sex hormone replacement therapy. The clinical symptoms of five patients improved, although one patient died of hepatic encephalopathy and multiple organ failure. CONCLUSIONS: HH can cause multiple endocrinopathies. The possibility of HH should be carefully considered in patients with endocrine gland dysfunctions and concomitant elevated serum ferritin levels. Endocrine gland function should also be assessed and followed up in patients with a clear diagnosis of HH.

Comparison of iron chelators used alone or in combination with phlebotomy in common mynahs (Acridotheres tristis) with experimental iron storage disease.

To compare the therapeutic effects of iron chelators used alone or in combination with phlebotomy on iron storage disease (ISD), 66 healthy common mynahs (Acridotheres tristis) were fed an iron-loading diet (3000 ppm) for 30 days. After confirmation of ISD, the birds were randomly divided into four treatment groups; DFO: deferoxamine (100 mg/kg SC q24 h), DFP: deferiprone (oral, 75 mg/kg), DFO + F: deferoxamine (100 mg/kg SC q24 h) with phlebotomy, and DFP + F: deferiprone (oral, 75 mg/kg) with phlebotomy. In phlebotomy-treated groups, blood sampling (1% BW) was performed weekly. At 1 and 2 months after treatments, seven birds from each group were euthanized and liver iron, copper, and zinc were analysed by ICP-OES assay. After 1 month, in all treatments, the liver amount of iron, copper, and zinc was reduced (P < 0.05) and there was no significant difference between groups. In the second month, the amount of liver iron, copper, and zinc decreased more in all groups, but this change was insignificant except in the DFP + F group (P < 0.05). These results suggest that all therapeutic protocols after 1 month effectively reduce the liver iron and there is no need to continue treatment. Otherwise, it may lead to iron deficiency, especially in birds treated with DFP + P. Since deferiprone, as an inexpensive oral chelator, effectively reduces liver iron levels without causing stress in the birds, it can be recommended as a more appropriate method for the treatment of mynahs with ISD. However, further clinical studies are needed to define the most effective treatment.RESEARCH HIGHLIGHTS Deferiprone is an optimized method for treating iron storage disease.The essential metals homeostasis is impaired in iron storage disease.

Hyperferritinaemia and iron overload in Asian patients: lessons from an Australian tertiary centre experience.

Iron overload is described in Asian patients but presents with a different phenotype and genotype compared to Caucasian patients. We retrospectively identified 64 Asian patients and compared them to 64 matched non-Asian patients with at least one episode of serum ferritin >500 µg/L. Of the Asian patients, one (1.6%) had proven iron overload, while other common causes of hyperferritinaemia included recent blood transfusion (47%), acute infection (11%) and haematological malignancy (8%). A greater proportion of non-Asian patients had hyperferritinaemia secondary to high alcohol intake. Iron overload is rare in Asians and unexplained hyperferritinaemia in Asian patients is more likely to be due to other factors.

Haemochromatosis in a kidney transplant recipient: a case report.

BACKGROUND: Iron overload is inevitably related to chronic kidney disease (CKD) treatment. Haemochromatosis leads to multiorgan damage and is associated with increased mortality. Primary haemochromatosis is the most common autosomal recessive disease in white populations. In most cases, the classic form of hereditary haemochromatosis is caused by mutations, mainly C282Y and H63D, in the haemochromatosis gene (HFE). Secondary haemochromatosis can be triggered by iron administration and blood transfusions. Haemochromatosis is rarely reported in kidney transplant recipients. Atypical factors may evoke haemochromatosis in patients without HFE mutations or other standard risk factors. CASE PRESENTATION: In the current study, we present a patient who started to have haemochromatosis symptoms after kidney transplantation. A 37-year-old man after kidney transplantation from a deceased donor was admitted to the hospital due to high serum ferritin levels and impaired graft function. The patient's past medical history included arterial hypertension, embolization of both renal arteries and necrosis of the left femoral head. Glomerulonephritis was suspected as a cause of CKD; however, severe kidney failure was diagnosed, kidney biopsy was not performed, and the patient started intermittent haemodialysis. While on dialysis to treat anaemia, the patient had received erythropoietin and iron intravenously, and the maximal serum ferritin level was 2115 ng/ml. After kidney transplantation, ferritin levels started to increase rapidly, with a maximum level of 9468 ng/ml one and a half years after surgery. His genetic study showed HFE C282Y heterozygosity. Symptoms of haemochromatosis, such as skin hyperpigmentation, elevated activity of aminotransferases, impaired glucose tolerance and heart failure, were observed. Therapeutic phlebotomy was started, and 36 procedures were performed. After treatment, graft function significantly improved, most haemochromatosis symptoms resolved, and the serum ferritin level significantly decreased. CONCLUSIONS: Haemochromatosis can occur in heterozygotic HFE patients after kidney transplantation. Iron administration, infections, type of immunosuppression and liver dysfunction should be considered potential triggers of haemochromatosis in this group of patients.

Genetic analysis of 39 erythrocytosis and hereditary hemochromatosis-associated genes in the Slovenian family with idiopathic erythrocytosis.

BACKGROUND: Erythrocytosis is a condition with an excessive number of erythrocytes, accompanied by an elevated haemoglobin and/or haematocrit value. Congenital erythrocytosis has a diverse genetic background with several genes involved in erythropoiesis. In clinical practice, nine genes are usually examined, but in approximately 70% of patients, no causative mutation can be identified. In this study, we screened 39 genes, aiming to identify potential disease-driving variants in the family with erythrocytosis of unknown cause. PATIENTS AND METHODS: Two affected family members with elevated haemoglobin and/or haematocrit and negative for acquired causes and one healthy relative from the same family were selected for molecular-genetic analysis of 24 erythrocytosis and 15 hereditary haemochromatosis-associated genes with targeted NGS. The identified variants were further analysed for pathogenicity using various bioinformatic tools and review of the literature. RESULTS: Of the 12 identified variants, two heterozygous variants, the missense variant c.471G>C (NM_022051.2) (p.(Gln157His)) in the EGLN1 gene and the intron variant c.2572-13A>G (NM_004972.3) in the JAK2 gene, were classified as low-frequency variants in European population. None of the two variants were present in a healthy family member. Variant c.2572-13A>G has potential impact on splicing by one prediction tool. CONCLUSION: For the first time, we included 39 genes in the erythrocytosis clinical panel and identified two potential disease-driving variants in the Slovene family studied. Based on the reported functional in vitro studies combined with our bioinformatics analysis, we suggest further functional analysis of variant in the JAK2 gene and evaluation of a cumulative effect of both variants.

The haemochromatosis gene Hfe and Kupffer cells control LDL cholesterol homeostasis and impact on atherosclerosis development.

AIMS: Imbalances of iron metabolism have been linked to the development of atherosclerosis. However, subjects with hereditary haemochromatosis have a lower prevalence of cardiovascular disease. The aim of our study was to understand the underlying mechanisms by combining data from genome-wide association study analyses in humans, CRISPR/Cas9 genome editing, and loss-of-function studies in mice. METHODS AND RESULTS: Our analysis of the Global Lipids Genetics Consortium (GLGC) dataset revealed that single nucleotide polymorphisms (SNPs) in the haemochromatosis gene HFE associate with reduced low-density lipoprotein cholesterol (LDL-C) in human plasma. The LDL-C lowering effect could be phenocopied in dyslipidaemic ApoE-/- mice lacking Hfe, which translated into reduced atherosclerosis burden. Mechanistically, we identified HFE as a negative regulator of LDL receptor expression in hepatocytes. Moreover, we uncovered liver-resident Kupffer cells (KCs) as central players in cholesterol homeostasis as they were found to acquire and transfer LDL-derived cholesterol to hepatocytes in an Abca1-dependent fashion, which is controlled by iron availability. CONCLUSION: Our results disentangle novel regulatory interactions between iron metabolism, KC biology and cholesterol homeostasis which are promising targets for treating dyslipidaemia but also provide a mechanistic explanation for reduced cardiovascular morbidity in subjects with haemochromatosis.

Gnpat does not play an essential role in systemic iron homeostasis in murine model.

The GNPAT variant rs11558492 (p.D519G) was identified as a novel genetic factor that modifies the iron-overload phenotype in homozygous carriers of the HFE p.C282Y variant. However, the reported effects of the GNPAT p.D519G variant vary among study populations. Here, we investigated the role of GNPAT in iron metabolism using Gnpat-knockout (Gnpat-/- ), Gnpat/Hfe double-knockout (Gnpat-/- Hfe-/- or DKO) mice and hepatocyte-specific Gnpat-knockout mice (Gnpatfl/fl ;Alb-Cre). Our analysis revealed no significant difference between wild-type (Gnpat+/+ ) and Gnpat-/- mice, between Hfe-/- and DKO mice, or between Gnpatfl/fl and Gnpatfl/fl ;Alb-Cre with respect to serum iron and tissue iron. In addition, the expression of hepcidin was not affected by deleting Gnpat expression in the presence or absence of Hfe. Feeding Gnpat-/- and DKO mice a high-iron diet had no effect on tissue iron levels compared with wild-type and Hfe-/- mice, respectively. Gnpat knockdown in primary hepatocytes from wild-type or Hfe-/- mice did not alter hepcidin expression, but it repressed BMP6-induced hepcidin expression. Taken together, these results support the hypothesis that deleting Gnpat expression has no effect on either systemic iron metabolism or the iron-overload phenotype that develops in Hfe-/- mice, suggesting that GNPAT does not directly mediate iron homeostasis under normal or high-iron dietary conditions.

Iron Through the Prism of Haematology.

Since the inception of the British Society for Haematology (BSH) 60 years ago, our increased scientific understanding of iron metabolism, together with clinical developments, have changed the way we diagnose and treat its disorders. In the UK, perhaps the most notable contributions relate to iron overload, some of which I will outline from personal experience. Diagnostically, this began with the identification of serum ferritin as a marker of iron overload and continued later with the application of MRI-based imaging techniques for iron and its distribution. Therapeutically, the first trials of both parenteral and oral chelation, which have radically changed the outcomes of transfusional iron-overloaded patients, took place in the UK and are now part of standard clinical practice. During this time, our scientific understanding of iron metabolism at a cellular and systemic level have advanced the diagnosis and treatment of inherited disorders of iron metabolism. There are potential novel applications related to our recent understanding of hepcidin metabolism and manipulation.

Massive iron overload and acute-on-chronic liver failure in a patient with Diamond-Blackfan anaemia: a case report.

BACKGROUND: Genetic anaemias lead us to reflect on the classic 'trolley dilemma', when there are two choices but neither one is satisfactory. Either we do not treat anaemia and the patient suffers from chronic tiredness and fatigue, or we do treat it through blood transfusions, leading to iron overload, which is a quite harmful consequence. CASE PRESENTATION: We present the case of a 34-year-old woman with Diamond-Blackfan anaemia (DBA). Bone marrow stem cell transplantation had not been accessible during her childhood, so she had been submitted to monthly blood transfusions throughout her life, leading to a hepatitis C virus infection (which was treated, achieving a sustained virological response when she was 18 years old), and secondary haemochromatosis. Despite chelation therapy, diffuse iron deposition was occurring in multiple organs, markedly in the heart and liver. Her serum ferritin was higher than 21,000 ng/mL and transferrin saturation reached 102%. When she faced heart decompensation, this congestive condition led to an acute liver injury overlapping pre-existing hepatic fibrosis. She progressed to haemodynamic and hepatic failure, with clinical features of acute-on-chronic liver failure (ACLF). Despite therapeutic optimisation, she died of respiratory insufficiency. An autopsy was performed and revealed the macroscopic and microscopic findings of a massive iron deposition in the liver, heart, lungs, spleen, bone marrow, thyroid and adrenal glands. We found marked advance of liver fibrosis (chronic damage), as well as necrosis of hepatocytes in zone 3 of the Rappaport acinus (acute damage), supporting the hypothesis of ACLF. The main feature responsible for acute liver decompensation seemed to be heart insufficiency. CONCLUSION: This is the first case reporting the sequence: DBA, multiple blood transfusions, secondary haemochromatosis, advanced liver fibrosis, heart failure, ACLF and death. A multidisciplinary team is essential to care for DBA patients, since there is a significant emotional burden related to the disease, which might impair an effective chelation therapy and lead to severe consequences due to iron deposition.

Detection of HFE Haemochromatosis in the clinic and community using standard erythrocyte tests.

Detection of HFE Haemochromatosis (HH) is challenging in the absence of clinical features. HH subjects have elevated erythrocyte parameters compared to those without HH, but it remains unclear how this could be applied in clinical practice. Thus, we determined the sensitivity, specificity and clinical utility of erythrocyte parameters in 144 HH subjects with (n = 122) or without (n = 22) clinical and/or biochemical expression of iron overload, 1844 general population controls, and 700 chronic disease subjects. For both expressing and non-expressing HH subjects, the mean pre- and post-phlebotomy values of mean cell volume (MCV) and mean cell haemoglobin (MCH) were always significantly higher when compared to all other groups and demonstrated excellent diagnostic utility for detection of HH in men and women (AUROC 0.83-0.9; maximal sensitivity and specificity 82% and 78%) using cut-off values for MCV >91 fL or MCH >31 pg, respectively. Between 34 and 62% of all HH subjects would be detected, and <4% of all non-HH subjects would undergo unnecessary testing, if those with MCV or MCH values >94 fL or 32.2 pg, respectively, were evaluated.

A novel SLC40A1 p.Y333H mutation with gain of function of ferroportin: A recurrent cause of haemochromatosis in China.

BACKGROUND & AIMS: Haemochromatosis type 4, also known as ferroportin disease, is an autosomal dominant genetic disorder caused by pathogenic mutations in the SLC40A1 gene, which encodes ferroportin 1 (FPN1). We have identified a novel SLC40A1 p.Y333H mutation in our previous study. In the present study, we tried to investigate the frequency and pathogenicity of the SLC40A1 p.Y333H mutation in haemochromatosis in China. METHODS: Patients were analysed for SLC40A1 p.Y333H as well as mutations in the other classic haemochromatosis-related genes by Sanger sequencing. To analyse iron export capacity of the SLC40A1 p.Y333H mutant, the 293T cells were transfected with the SLC40A1 p.Y333H construct and then treated with hepcidin after exposure to ferric ammonium citrate. Cellular localization of mutant FPN1, expression of FPN1 and intracellular ferritin were analysed by immunofluorescence and Western blotting. RESULTS: Of 22 unrelated cases with primary iron overload, three cases (3/22, 13.6%) harboured the SLC40A1 p.Y333H, with no missense mutations identified in any other classical haemochromatosis-related genes including HFE, HJV, HAMP and TFR2. Pedigree analysis showed that three probands and the son of one proband had haemochromatosis of stage 3, while the son of another proband with age of 16 showed elevated transferrin saturation but normal serum ferritin level. In vitro studies showed the mutant p.Y333H ferroportin was resistant to hepcidin, affecting the subsequent internalization and degradation of FPN1, and was associated with ferroportin gain of function. CONCLUSIONS: The SLC40A1 p.Y333H mutation is associated with gain of function of ferroportin, representing one of the major aetiological factors of haemochromatosis in China.

Mild Hereditary Spherocytosis without Accompanying Hereditary Haemochromatosis: An Unrecognised Cause of Iron Overload.

Hereditary spherocytosis (HS) is a common inherited haemolytic anaemia and has great variability in its presentation. Non-transfusion iron overload in HS has only been reported with co-inheritance of hereditary haemochromatosis (HHC). We present 4 unrelated patients of East Asian ethnicity with mild HS and significant non-transfusion iron overload in the absence of known disease-causing mutations in HHC genes. We hypothesise that, in patients with mild HS, life-long chronic haemolysis and erythropoietic drive may promote iron absorption. This suggests that mild HS may not be entirely benign, and that patients with mild HS should be monitored for iron overload.