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Jormakka M. Structural insights into ferroportin mediated iron transport. Biochem Soc Trans 2023; 51:BST20230594. [PMID: 38115725 DOI: 10.1042/bst20230594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 12/08/2023] [Accepted: 12/11/2023] [Indexed: 12/21/2023]
Abstract
Iron is a vital trace element for almost all organisms, and maintaining iron homeostasis is critical for human health. In mammals, the only known gatekeeper between intestinally absorbed iron and circulatory blood plasma is the membrane transporter ferroportin (Fpn). As such, dysfunction of Fpn or its regulation is a key driver of iron-related pathophysiology. This review focuses on discussing recent insights from high-resolution structural studies of the Fpn protein family. While these studies have unveiled crucial details of Fpn regulation and structural architecture, the associated functional studies have also at times provided conflicting data provoking more questions than answers. Here, we summarize key findings and illuminate important remaining questions and contradictions.
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Affiliation(s)
- Mika Jormakka
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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2
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Kowdley KV, Modi NB, Peltekian K, Vierling JM, Ferris C, Valone FH, Gupta S. Rusfertide for the treatment of iron overload in HFE-related haemochromatosis: an open-label, multicentre, proof-of-concept phase 2 trial. Lancet Gastroenterol Hepatol 2023; 8:1118-1128. [PMID: 37863080 DOI: 10.1016/s2468-1253(23)00250-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 07/23/2023] [Accepted: 07/27/2023] [Indexed: 10/22/2023]
Abstract
BACKGROUND Hereditary haemochromatosis protein (HFE)-related haemochromatosis, an inherited iron overload disorder caused by insufficient hepcidin production, results in excessive iron absorption and tissue and organ injury, and is treated with first-line therapeutic phlebotomy. We aimed to investigate the efficacy and safety of rusfertide, a peptidic mimetic of hepcidin, in patients with HFE-related haemochromatosis. METHODS This open-label, multicentre, proof-of-concept phase 2 trial was done across nine academic and community centres in the USA and Canada. Adults (aged ≥18 years) with HFE-related haemochromatosis on a stable therapeutic phlebotomy regimen (maintenance phase) for at least 6 months before screening and who had a phlebotomy frequency of at least 0·25 per month (eg, at least three phlebotomies in 12 months or at least four phlebotomies in 15 months) and less than one phlebotomy per month, with serum ferritin of less than 300 ng/mL and haemoglobin of more than 11·5 g/dL, were eligible. Patients initiated 24 weeks of subcutaneous rusfertide treatment within 7 days of a scheduled phlebotomy at 10 mg once weekly. Rusfertide doses and dosing schedules could be adjusted to maintain serum transferrin iron saturation (TSAT) at less than 40%. During rusfertide treatment, investigators were to consider the need for phlebotomy when the serum ferritin and TSAT values exceeded the patient's individual pre-phlebotomy serum ferritin and TSAT values. No primary endpoint or testing hierarchy was prespecified. Prespecified efficacy endpoints included the change in the frequency of phlebotomies; the proportion of patients achieving phlebotomy independence; change in serum iron, TSAT, serum transferrin, serum ferritin, and liver iron concentration (LIC) as measured by MRI; and treatment-emergent adverse events (TEAEs). The key efficacy analyses for phlebotomy rate and LIC were conducted by use of paired t tests in the intention-to-treat population, defined as all patients who received any study drug and who had pretreatment and at least one post-dose measurement. We included all participants who received at least one dose of rusfertide in the safety analyses. This trial is closed and completed and is registered with ClinicalTrials.gov, NCT04202965. FINDINGS Between March 11, 2020, and April 23, 2021, 28 patients were screened and 16 (ten [63%] men and six [38%] women) were enrolled. 16 were included in analyses of phlebotomy endpoints and 14 for the LIC endpoint. 12 (75%) patients completed 24 weeks of treatment. The mean number of phlebotomies was significantly reduced during the 24-week rusfertide treatment (0·06 phlebotomies [95% CI -0·07 to 0·20]) compared with 24 weeks pre-study (2·31 phlebotomies [95% CI 1·77 to 2·85]; p<0·0001). 15 (94%) of 16 patients were phlebotomy-free during the treatment period. Mean LIC in the 14 patients in the intention-to-treat population was 1·4 mg iron per g dry liver weight (95% CI 1·0 to 1·8) at screening and 1·1 mg iron per g dry liver weight (95% CI 0·9 to 1·3) at the end of treatment (p=0·068). Mean TSAT was 45·3% (95% CI 33·2 to 57·3) at screening, 36·7% (24·2 to 49·2) after the pretreatment phlebotomy, 21·8% (15·8 to 27·9) 24 h after the first dose of rusfertide, 40·4% (27·1 to 53·8) at the end of treatment, and 32·6% (25·0 to 40·1) over the treatment duration. Mean serum iron was 24·6 μmol/L (95% CI 18·6 to 30·6), 20·1 μmol/L (14·8 to 25·3), 11·9 μmol/L (9·2 to 14·7), 22·5 μmol/L (15·9 to 29·1), and 19·0 μmol/L (15·3 to 22·6) at these same timepoints, respectively. Mean serum ferritin was 83·3 μg/L (52·2 to 114.4), 65·5 μg/L (32·1 to 98·9), 62·8 μg/L (33·8 to 91·9), 150·0 μg/L (86·6 to 213.3), and 94·3 μg/L (54·9 to 133.6) at these same timepoints, respectively. There were only minor changes in serum transferrin concentration. 12 (75%) patients had at least one TEAE, the most common of which was injection site pain (five [31%] patients). All TEAEs were mild or moderate in severity, except for a serious adverse event of pancreatic adenocarcinoma, which was considered severe and unrelated to treatment and was pre-existing and diagnosed 21 days after starting rusfertide treatment. INTERPRETATION Rusfertide prevents iron re-accumulation in the absence of phlebotomies and could be a viable therapeutic option for selected patients with haemochromatosis. FUNDING Protagonist Therapeutics.
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Affiliation(s)
- Kris V Kowdley
- Liver Institute Northwest, Seattle, WA, USA; Elson S Floyd College of Medicine, Washington State University, Seattle, WA, USA.
| | | | - Kevork Peltekian
- Division of Digestive Care and Endoscopy, Department of Medicine, Dalhousie University, Halifax, NS, Canada
| | - John M Vierling
- Section of Gastroenterology and Hepatology and Division of Abdominal Transplantation, Baylor College of Medicine, Houston, TX, USA
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3
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Crawford DHG, Ramm GA, Bridle KR, Nicoll AJ, Delatycki MB, Olynyk JK. Clinical practice guidelines on hemochromatosis: Asian Pacific Association for the Study of the Liver. Hepatol Int 2023; 17:522-541. [PMID: 37067673 DOI: 10.1007/s12072-023-10510-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 02/28/2023] [Indexed: 04/18/2023]
Affiliation(s)
- Darrell H G Crawford
- Faculty of Medicine, The University of Queensland, Brisbane, Australia
- Gallipoli Medical Research Foundation, Brisbane, Australia
| | - Grant A Ramm
- Faculty of Medicine, The University of Queensland, Brisbane, Australia
- Hepatic Fibrosis Group, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Kim R Bridle
- Faculty of Medicine, The University of Queensland, Brisbane, Australia.
- Gallipoli Medical Research Foundation, Brisbane, Australia.
| | - Amanda J Nicoll
- Department of Gastroenterology, Eastern Health, Box Hill, VIC, Australia
- Monash University, Melbourne, VIC, Australia
| | - Martin B Delatycki
- Bruce Lefroy Centre, Murdoch Children's Research Institute, Melbourne, VIC, Australia
- The University of Melbourne, Melbourne, VIC, Australia
- Victorian Clinical Genetics Services, Parkville, VIC, Australia
| | - John K Olynyk
- Department of Gastroenterology, Fiona Stanley Hospital, Murdoch, WA, Australia
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
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4
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A Novel Hepcidin Mutation. Transfus Clin Biol 2023:S1246-7820(23)00037-X. [PMID: 36925058 DOI: 10.1016/j.tracli.2023.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 03/02/2023] [Accepted: 03/02/2023] [Indexed: 03/18/2023]
Abstract
BACKGROUND The bioactive peptide hormone hepcidin-25 regulates iron levels by inhibiting iron transport to plasma via ferroportin. Hepcidin-25 is synthesized in the liver where the 84 amino acids pro-hepcidin is cleaved into the bioactive hepcidin-25. A patient admitted to the hospital presented with infertility and fatigue. METHODS Genomic DNA was purified from whole blood using the Maxwell 16 system (Promega). MLPA analysis was performed to detect large genomic rearrangements using the SALSA MLPA kit # P347, Hemochromatosis (MRC Holland, Holland). Plasma hepcidin measurements were performed using liquid chromatography/tandem mass spectrometry (LC-MS/MS). RESULTS A novel HAMP mutation (homozygous one base deletion in c.215delG, p.Cys72Serfs*?) was detected. The deletion in nucleotide 215 causes a frameshift altering the predicted protein sequence from cysteine13 in mature peptide. Whether this leads to nonsense mediated decay of the mRNA or synthesis of an aberrant peptide in unknown, but bioactive hepcidin-25 was undetectable in plasma. The patient had massive iron overload with ferritin up to 8360 µg/L. He was anaemic with a Hb at 7.0 mmol/L (11.3 g/dL) and suffered from hypogonadotropic hypogonadism with a total testosterone of 1.2 nmol/l . Continued treatment with venesection and gonadotropins led to reduced fatigue, reduction in iron overload, a normalized Hb and improvement of semen quality. CONCLUSION A novel hepcidin mutation was detected in a patient with massive iron overload, fatigue and hypogonadotropic hypogonadism.
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Positive or U-Shaped Association of Elevated Hemoglobin Concentration Levels with Metabolic Syndrome and Metabolic Components: Findings from Taiwan Biobank and UK Biobank. Nutrients 2022; 14:nu14194007. [PMID: 36235661 PMCID: PMC9572591 DOI: 10.3390/nu14194007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 09/21/2022] [Accepted: 09/22/2022] [Indexed: 11/17/2022] Open
Abstract
Iron overnutrition has been implicated with a higher risk of developing metabolic and cardiovascular diseases, including metabolic syndrome (MetS), whereas iron deficiency anemia exacerbates many underlying chronic conditions. Hemoglobin (Hb) concentration in the blood, which reflects a major functional iron (i.e., heme iron) in the body, may serve as a surrogate of the nutritional status of iron. We conducted sex-specific observational association studies in which we carefully titrated the association between Hb deciles and MetS and its components among the Taiwanese Han Chinese (HC) from the Taiwan Biobank and Europeans of White ancestry from the UK Biobank, representing two large ethnicities. Our data show that at higher-than-normal levels of Hb, increasing deciles of Hb concentration were significantly associated with MetS across all sex subgroups in both ethnicities, with the highest deciles resulting in up to three times greater risk than the reference group [Taiwanese HC: OR = 3.17 (95% CI, 2.75-3.67) for Hb ≥ 16.5 g/dL in men, OR = 3.11 (2.78-3.47) for Hb ≥ 14.5 g/dL in women; European Whites: OR = 1.89 (1.80-1.98) for Hb ≥ 16.24 g/dL in men, OR = 2.35 (2.24-2.47) for Hb ≥ 14.68 g/dL in women]. The association between stronger risks and increasing Hb deciles was similarly observed with all metabolic components except diabetes. Here we found that both the highest Hb decile groups and contrarily the lowest ones, with respect to the reference, were associated with higher odds of diabetes in both ethnic groups [e.g., Taiwanese HC men: OR = 1.64 (1.33-2.02) for Hb ≥ 16.5 g/dL, OR = 1.71 (1.39-2.10) for Hb ≤ 13.5 g/dL; European Whites women: OR = 1.39 (1.26-1.45) for Hb ≥ 14.68 g/dL, OR = 1.81 (1.63-2.01) for Hb ≤ 12.39 g/dL]. These findings confirm that elevated Hb concentrations, a potential indicator of iron overnutrition, may play a role in the pathophysiology of MetS and metabolic components.
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Girelli D, Busti F, Brissot P, Cabantchik I, Muckenthaler MU, Porto G. Hemochromatosis classification: update and recommendations by the BIOIRON Society. Blood 2022; 139:3018-3029. [PMID: 34601591 PMCID: PMC11022970 DOI: 10.1182/blood.2021011338] [Citation(s) in RCA: 56] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 09/05/2021] [Indexed: 12/15/2022] Open
Abstract
Hemochromatosis (HC) is a genetically heterogeneous disorder in which uncontrolled intestinal iron absorption may lead to progressive iron overload (IO) responsible for disabling and life-threatening complications such as arthritis, diabetes, heart failure, hepatic cirrhosis, and hepatocellular carcinoma. The recent advances in the knowledge of pathophysiology and molecular basis of iron metabolism have highlighted that HC is caused by mutations in at least 5 genes, resulting in insufficient hepcidin production or, rarely, resistance to hepcidin action. This has led to an HC classification based on different molecular subtypes, mainly reflecting successive gene discovery. This scheme was difficult to adopt in clinical practice and therefore needs revision. Here we present recommendations for unambiguous HC classification developed by a working group of the International Society for the Study of Iron in Biology and Medicine (BIOIRON Society), including both clinicians and basic scientists during a meeting in Heidelberg, Germany. We propose to deemphasize the use of the molecular subtype criteria in favor of a classification addressing both clinical issues and molecular complexity. Ferroportin disease (former type 4a) has been excluded because of its distinct phenotype. The novel classification aims to be of practical help whenever a detailed molecular characterization of HC is not readily available.
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Affiliation(s)
- Domenico Girelli
- Department of Medicine, Section of Internal Medicine, EuroBloodNet Center, University of Verona and Azienda Ospedaliera Universitaria Integrata Verona, Verona, Italy
| | - Fabiana Busti
- Department of Medicine, Section of Internal Medicine, EuroBloodNet Center, University of Verona and Azienda Ospedaliera Universitaria Integrata Verona, Verona, Italy
| | - Pierre Brissot
- INSERM, Univ-Rennes, Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1241, Institut NuMeCan, Rennes, France
| | - Ioav Cabantchik
- Alexander Silberman Institute of Life Sciences, Hebrew University, Jerusalem, Israel
| | - Martina U. Muckenthaler
- Department of Pediatric Oncology, Hematology, and Immunology and Molecular Medicine Partnership Unit, University of Heidelberg, Heidelberg, Germany
- Molecular Medicine Partnership Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Translational Lung Research Center, German Center for Lung Research, Heidelberg, Germany
- German Centre for Cardiovascular Research, Partner Site Heidelberg, Mannheim, Germany
| | - Graça Porto
- Institute for Molecular and Cell Biology, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Clinical Hematology, Santo António Hospital, Porto University, Porto, Portugal
| | - on behalf of the Nomenclature Committee of the International Society for the Study of Iron in Biology and Medicine (BIOIRON Society)
- Department of Medicine, Section of Internal Medicine, EuroBloodNet Center, University of Verona and Azienda Ospedaliera Universitaria Integrata Verona, Verona, Italy
- INSERM, Univ-Rennes, Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1241, Institut NuMeCan, Rennes, France
- Alexander Silberman Institute of Life Sciences, Hebrew University, Jerusalem, Israel
- Department of Pediatric Oncology, Hematology, and Immunology and Molecular Medicine Partnership Unit, University of Heidelberg, Heidelberg, Germany
- Molecular Medicine Partnership Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Translational Lung Research Center, German Center for Lung Research, Heidelberg, Germany
- German Centre for Cardiovascular Research, Partner Site Heidelberg, Mannheim, Germany
- Institute for Molecular and Cell Biology, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Clinical Hematology, Santo António Hospital, Porto University, Porto, Portugal
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Hepatitis B-Associated Symptomatic Iron Overload, with Complete Resolution after Nucleoside Analogue Treatment. Case Rep Gastrointest Med 2022; 2021:8407257. [PMID: 34987872 PMCID: PMC8723841 DOI: 10.1155/2021/8407257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 12/10/2021] [Accepted: 12/16/2021] [Indexed: 11/17/2022] Open
Abstract
Symptomatic iron overload and hyperferritinemia are rarely mentioned as complications of chronic hepatitis B infection. We report a case of a 70-year-old woman who presented with symptoms of iron overload including aches in the calves, fatigue, poor appetite, and low mood. Laboratory results showed a serum ferritin of 2449 μg/L and transferrin saturation of 74%. Her symptoms completely resolved with hepatitis B antiviral treatment. Serum ferritin and transferrin saturation also normalized. Symptomatic iron overload is a rare yet clinically important complication that can result from chronic hepatitis B infection.
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8
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Con D, Nicoll AJ. Hyperferritinaemia and iron overload in Asian patients: lessons from an Australian tertiary centre experience. Intern Med J 2021; 51:802-805. [PMID: 34047022 DOI: 10.1111/imj.15316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 04/14/2020] [Accepted: 04/15/2020] [Indexed: 11/28/2022]
Abstract
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.
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Affiliation(s)
- Danny Con
- Department of Gastroenterology, Eastern Health, Melbourne, Victoria, Australia
| | - Amanda J Nicoll
- Department of Gastroenterology, Eastern Health, Melbourne, Victoria, Australia.,Eastern Health Clinical School, Monash University, Melbourne, Victoria, Australia
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Kang W, Barad A, Clark AG, Wang Y, Lin X, Gu Z, O'Brien KO. Ethnic Differences in Iron Status. Adv Nutr 2021; 12:1838-1853. [PMID: 34009254 PMCID: PMC8483971 DOI: 10.1093/advances/nmab035] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/02/2021] [Accepted: 03/05/2021] [Indexed: 02/07/2023] Open
Abstract
Iron is unique among all minerals in that humans have no regulatable excretory pathway to eliminate excess iron after it is absorbed. Iron deficiency anemia occurs when absorbed iron is not sufficient to meet body iron demands, whereas iron overload and subsequent deposition of iron in key organs occur when absorbed iron exceeds body iron demands. Over time, iron accumulation in the body can increase risk of chronic diseases, including cirrhosis, diabetes, and heart failure. To date, only ∼30% of the interindividual variability in iron absorption can be captured by iron status biomarkers or iron regulatory hormones. Much of the regulation of iron absorption may be under genetic control, but these pathways have yet to be fully elucidated. Genome-wide and candidate gene association studies have identified several genetic variants that are associated with variations in iron status, but the majority of these data were generated in European populations. The purpose of this review is to summarize genetic variants that have been associated with alterations in iron status and to highlight the influence of ethnicity on the risk of iron deficiency or overload. Using extant data in the literature, linear mixed-effects models were constructed to explore ethnic differences in iron status biomarkers. This approach found that East Asians had significantly higher concentrations of iron status indicators (serum ferritin, transferrin saturation, and hemoglobin) than Europeans, African Americans, or South Asians. African Americans exhibited significantly lower hemoglobin concentrations compared with other ethnic groups. Further studies of the genetic basis for ethnic differences in iron metabolism and on how it affects disease susceptibility among different ethnic groups are needed to inform population-specific recommendations and personalized nutrition interventions for iron-related disorders.
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Affiliation(s)
- Wanhui Kang
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
| | - Alexa Barad
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
| | - Andrew G Clark
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA,Department of Computational Biology, Cornell University, Ithaca, NY, USA
| | - Yiqin Wang
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
| | - Xu Lin
- Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, China
| | - Zhenglong Gu
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
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Alqanatish J, Alsowailmi B, Alfarhan H, Alhamzah A, Alharbi T. Juvenile Hemochromatosis: Rheumatic Manifestations of 2 Sisters Responding to Deferasirox Treatment. A Case Series and Literature Review. Open Access Rheumatol 2021; 13:15-21. [PMID: 33488128 PMCID: PMC7815067 DOI: 10.2147/oarrr.s276112] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 10/27/2020] [Indexed: 12/24/2022] Open
Abstract
Hereditary hemochromatosis (HH) is an inherited iron overload. The most common form of HH is type 1 hereditary hemochromatosis (HFE-related), which is associated with mutation of the HFE gene located on chromosome 6 and inherited in an autosomal recessive pattern. Type 2 hereditary hemochromatosis or juvenile hemochromatosis is less frequent autosomal recessive disease that results from mutations in the HJV gene on chromosome 1 (type2a) or the HAMP gene on chromosome19 (type2b). Mutation of type 2 transferrin receptor gene and mutation of the ferroportin gene result in hemochromatosis type 3 and hemochromatosis type 4, respectively. Juvenile hemochromatosis is characterized by an early onset of excess accumulation of iron in various organs. It could affect the liver, heart, pancreas and joints, resulting in arthropathy. Most juvenile hemochromatosis cases exhibit severe symptoms due to early onset. Cardiac and hypogonadism are the dominating features of the disease. Prevalence of arthropathy in juvenile hemochromatosis is higher than classic HH. Early diagnosis and intervention of juvenile hemochromatosis may prevent irreversible organ damage. The diagnosis can be made based on laboratory testing (of increased transferrin saturation, serum iron and ferritin levels), liver biopsy, imaging or genotype. According to international guidelines, treatment of HH is indicated when serum ferritin concentrations are above the upper limit of normal. We report two sisters who presented to the rheumatology clinic with arthralgia, which was subsequently found to have a homozygous mutation variant of unknown significance in the HFE2 gene: c.497A>G;p.(His166Arg) and has been treated with deferasirox (Exjade®). Musculoskeletal symptoms completely resolved in both patients in two months and remained so for one year on treatment.
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Affiliation(s)
- Jubran Alqanatish
- King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Riyadh 14611, Saudi Arabia.,King Abdullah International Medical Research Center (KAIMRC), Riyadh 14611, Saudi Arabia.,Department of Pediatrics, King Abdullah Specialist Children's Hospital and King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
| | - Banan Alsowailmi
- King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Riyadh 14611, Saudi Arabia
| | - Haneen Alfarhan
- King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Riyadh 14611, Saudi Arabia
| | - Albandari Alhamzah
- King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Riyadh 14611, Saudi Arabia
| | - Talal Alharbi
- King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Riyadh 14611, Saudi Arabia.,King Abdullah International Medical Research Center (KAIMRC), Riyadh 14611, Saudi Arabia.,Department of Pediatric Hematology/Oncology, King Abdullah Specialist Children's Hospital and King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
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11
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Goyal A, Mohan B, Saggar K, Wander GS. Primary haemochromatosis resulting in dilated cardiomyopathy arising out of mutation in HJV gene in Indian patients: a rare scenario. BMJ Case Rep 2020; 13:13/9/e235650. [PMID: 32938653 DOI: 10.1136/bcr-2020-235650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Primary haemochromatosis (PH) is a genetic disorder of iron metabolism with multiorgan involvement due to mutations in HFE or more rarely haemojuvelin (HJV) gene. Cardiac involvement results in dilated cardiomyopathy with reduced ejection fraction and progressive heart failure. PH is rarely reported from India and cardiomyopathy due to PH from HJV mutations is thought to be uncommon. We report two families with cardiomyopathy resulting from PH. Diagnosis was suspected on the basis of skin pigmentation, markedly elevated serum ferritin and transferring saturation. Genetic testing revealed a rare mutation in HJV gene in one family. Being a treatable condition, PH should be suspected and investigated in cardiomyopathy patients in Indian subcontinent. If HFE is negative, analysis of non-HFE mutation should always be considered.
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Affiliation(s)
- Abhishek Goyal
- Cardiology, Hero DMC heart institute, Dayanand Medical College and Hospital, Ludhiana, Punjab, India
| | - Bishav Mohan
- Cardiology, Hero DMC heart institute, Dayanand Medical College and Hospital, Ludhiana, Punjab, India
| | - Kavita Saggar
- Radiology, Dayanand Medical College and Hospital, Ludhiana, Punjab, India
| | - Gurpreet Singh Wander
- Cardiology, Hero DMC heart institute, Dayanand Medical College and Hospital, Ludhiana, Punjab, India
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12
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Juvenile Hemochromatosis: A Case Report and Review of the Literature. Pharmaceuticals (Basel) 2020; 13:ph13080195. [PMID: 32824233 PMCID: PMC7465211 DOI: 10.3390/ph13080195] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 08/12/2020] [Accepted: 08/14/2020] [Indexed: 12/12/2022] Open
Abstract
Juvenile hemochromatosis (JH), type 2A hemochromatosis, is a rare autosomal recessive disorder of systemic iron overload due to homozygous mutations of HJV (HFE2), which encodes hemojuvelin, an essential regulator of the hepcidin expression, causing liver fibrosis, diabetes, and heart failure before 30 years of age, often with fatal outcomes. We report two Japanese sisters of 37 and 52 years of age, with JH, who showed the same homozygous HJV I281T mutation and hepcidin deficiency and who both responded well to phlebotomy on an outpatient basis. When all reported cases of JH with homozygous HJV mutations in the relevant literature were reviewed, we found—for the first time—that JH developed in females and males at a ratio of 3:2, with no age difference in the two groups. Furthermore, we found that the age of onset of JH may depend on the types of HJV mutations. In comparison to patients with the most common G320V/G320V mutation, JH developed earlier in patients with L101P/L101P or R385X/R385X mutations and later in patients with I281T/I281T mutations.
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13
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Wickramasinghe W, Karunathilaka C, Jayasinghe S, Gooneratne L. Transient elevation of serum ferritin in a Sri Lankan with homozygosity for H63D mutation in the HFE gene: a case report. J Med Case Rep 2020; 14:93. [PMID: 32641120 PMCID: PMC7346448 DOI: 10.1186/s13256-020-02428-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 06/01/2020] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION Hereditary hemochromatosis is an inherited disorder of iron metabolism, characterized by excessive iron deposition in major organs of the body, leading to multi-organ dysfunction. It is a genetically heterogeneous disease caused by mutations in one or more different genes, the most common being mutations in the HFE gene. HFE hereditary hemochromatosis is mostly found in Europeans and is almost always a result of two mutations: C282Y and H63D. The H63D mutation is not as penetrant as the C282Y mutation, but there are rare reported cases of hereditary hemochromatosis with homozygous H63D genotype. While the C282Y mutation is primarily confined to persons of Northern European origin, the H63D mutation is spread worldwide. Other types of hereditary hemochromatosis are rare and broadly defined as non-HFE hereditary hemochromatosis and include mutations in the hemojuvelin gene, hepcidin (HAMP gene), transferrin receptor 2 gene, and ferroportin gene. Hereditary hemochromatosis is commonly found in populations of European origin; in contrast, it is rare and less well understood in Asia. It can be masked by the presence of concurrent iron deficiency or secondary iron overload in thalassemias. CASE PRESENTATION We report the case of a 42-year-old Sri Lankan man investigated for fatigue during a brief upper respiratory tract infection and found to have high liver transaminases and high serum ferritin, which persisted even after complete resolution of the infection. Homozygosity for H63D mutation in the HFE gene was detected. Liver enzymes, serum ferritin, and transferrin saturation normalized following venesections. CONCLUSION This case adds to the literature on the importance of being vigilant and investigating patients suspected for iron overload, including genetic studies for hereditary hemochromatosis, even though it is a rare clinical entity in Asians.
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Affiliation(s)
| | | | - Saroj Jayasinghe
- Department of Pathology, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
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Hashmi G, Qidwai A, Fernandez K, Seul M. Enabling routine β-thalassemia Prevention and Patient Management by scalable, combined Thalassemia and Hemochromatosis Mutation Analysis. BMC MEDICAL GENETICS 2020; 21:108. [PMID: 32414341 PMCID: PMC7229588 DOI: 10.1186/s12881-020-01017-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Accepted: 03/31/2020] [Indexed: 01/19/2023]
Abstract
BACKGROUND Beta (β)-thalassemia is one of the most common inherited disorders worldwide, with high prevalence in the Mediterranean, the Middle East and South Asia. Over the past 40 years, awareness and prevention campaigns in many countries have greatly reduced the incidence of affected child births. In contrast, much remains to be done in South-Asia. Thus, for Pakistan, an estimated ~ 7000 children annually are born with thalassemia, with no sign of improvement. Although there is good agreement that intermarriage of carriers significantly contributes to the high prevalence of the disorder, effective tools for molecular screening and diagnosis on which to base prevention programs are not readily available. METHODS Here, we present results for a novel LeanSequencing™ process to identify a combination of 18 β-thalassemia mutations (including the sickle cell anemia mutation, HbS, and structural variants HbC and HbE) and 2 hemochromatosis mutations in a multi-ethnic population of 274 pediatric and adolescent patients treated at Afzaal Memorial Thalassemia Foundation in Karachi, Pakistan. RESULTS We found substantial differences in the predominance of disease-causing mutations among the principal ethnic groups in our cohort. We also found the hemochromatosis mutation H63D C > G in 61 (or 22.1%) of our patients including 6 (or 2.2%) homozygotes. CONCLUSIONS To our knowledge, this is the first screen combining a large set of β-thalassemia and hemochromatosis mutations, so as to facilitate the early identification of patients who may be at increased potential risk for complications from iron overload and thereby to improve the prospective management of thalassemia patients.
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Affiliation(s)
- Ghazala Hashmi
- BioMolecular Analytics, 10 Independence Blvd, Suite 140, Warren, NJ, 07059, USA.,Sanya K Hashmi Foundation, 56 Telegraph Hill Road, Holmdel, NJ, 07733, USA
| | - Asim Qidwai
- Afzaal Memorial Thalassemia Foundation, Karachi, Pakistan
| | | | - Michael Seul
- BioMolecular Analytics, 10 Independence Blvd, Suite 140, Warren, NJ, 07059, USA.
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Barton JC, Barton JC, Adams PC. Prevalence and characteristics of anti-HCV positivity and chronic hepatitis C virus infection in HFE p.C282Y homozygotes. Ann Hepatol 2020; 18:354-359. [PMID: 31056361 DOI: 10.1016/j.aohep.2018.11.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 10/30/2018] [Accepted: 11/28/2018] [Indexed: 02/04/2023]
Abstract
INTRODUCTION AND AIM Observations of hepatitis C virus (HCV) infection in adults with hemochromatosis are limited. MATERIALS AND METHODS We determined associations of serum ferritin (SF) with anti-HCV in non-Hispanic white North American adults in a post-screening examination. Cases included p.C282Y homozygotes (regardless of screening transferrin saturation (TS) and SF) and participants (regardless of HFE genotype) with high screening TS/SF. Controls included participants without p.C282Y or p.H63D who had normal screening TS/SF. Participants with elevated alanine aminotransferase underwent anti-HCV testing. We determined prevalence of chronic HCV infection in consecutive Alabama and Ontario referred adults with HFE p.C282Y homozygosity. RESULTS In post-screening participants, anti-HCV prevalence was 0.3% [95% CI: 0.02, 2.2] in 294 p.C282Y homozygotes, 9.5% [7.2, 12.3] in 560 Cases without p.C282Y homozygosity, and 0.7% [0.2, 2.3] in 403 Controls. Anti-HCV was detected in 7.2% of 745 participants with and 0.8% of 512 participants without elevated SF (odds ratio 9.9 [3.6, 27.6]; p<0.0001). Chronic HCV infection prevalence in 961 referred patients was 1.0% (10/961) [95% confidence interval (CI): 0.5, 2.0]. Ten patients with chronic HCV infection had median age 45y (range 29-67) and median SF 1163μg/L (range 303-2001). Five of eight (62.5%) patients had biopsy-proven cirrhosis. CONCLUSIONS Odds ratio of anti-HCV was increased in post-screening participants with elevated SF. Prevalence of anti-HCV in post-screening participants with HFE p.C282Y homozygosity and chronic HCV infection in referred adults with HFE p.C282Y homozygosity in North America is similar to that of Control participants with HFE wt/wt and normal screening TS/SF.
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Affiliation(s)
- James C Barton
- Southern Iron Disorders Center, Birmingham, Birmingham, AL, USA; Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.
| | | | - Paul C Adams
- Department of Medicine, University of Western Ontario, London, Ontario, Canada
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Koshy A, Mukkada RJ, Chettupuzha AP, Francis JV, Kandathil JC, Mahadevan P. Hemochromatosis in India: First Report of Whole Exome Sequencing With Review of the Literature. J Clin Exp Hepatol 2020; 10:163-169. [PMID: 32189932 PMCID: PMC7067988 DOI: 10.1016/j.jceh.2019.04.051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 04/17/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Primary hemochromatosis is unusual in India. The homeostatic iron regulator (HFE) gene C282Y mutation, a common cause for hemochromatosis in Europe, is considered almost nonexistent in India. We are reporting a case of hemochromatosis with the HFE gene C282Y mutation and two other adult cases with a novel hemojuvelin (HJV) mutation from Kerala. METHODS Of 434 cases with chronic liver disease, 3 cases were identified with the serum ferritin level of more than 1000 ng/mL and primary hemochromatosis after excluding secondary causes. Whole exome sequencing, including genes HFE, HJV, SLC40A1, TFR2, FTH1, HAMP, SKIV2L, TTC37, and BMP2, was performed for blood samples in all 3 cases. RESULTS One patient with hemochromatosis had a homozygous HFE gene C282Y mutation, and two other adult cases had a novel homozygous HJV D355Y mutation. This is the first report of hemochromatosis associated with the HFE C282Y mutation from Kerala and the second report in India. This is the second report of hemochromatosis associated with an HJV mutation from India. CONCLUSION HJV mutations may explain some of the adult onset primary hemochromatosis in India.
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Affiliation(s)
- Abraham Koshy
- Departments of Gastroenterology, VPS Lakeshore Hospital, Kochi, India
- Address for correspondence: Professor Abraham Koshy, Department of Gastroenterology Lakeshore Hospital, Kochi 682304, India. Tel: +91 484 701032; fax: +91 484 701996.
| | - Roy J. Mukkada
- Departments of Gastroenterology, VPS Lakeshore Hospital, Kochi, India
| | | | - Jose V. Francis
- Departments of Gastroenterology, VPS Lakeshore Hospital, Kochi, India
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Abstract
Iron is an essential micronutrient for oxygen transport, cellular energy metabolism, and many enzymatic reactions. Complex physiological processes have evolved for iron acquisition to meet metabolic needs while avoiding toxicity from iron-generated free radicals. Systemic iron homeostasis is centered around the regulation of iron absorption from duodenum and iron release from stores by hepcidin. Intracellular iron is maintained under tight control by iron regulatory proteins acting at post-transcriptional level. Despite these elaborate mechanisms, iron status is frequently altered by environmental or genetic influences. Iron deficiency anemia is the most common nutritional disorder affecting a quarter of the world population. Iron deficiency is associated with impaired cognitive development and reduced capacity for physical work, making it a high priority for public health initiatives. Chronic inflammation from infections or other causes limits iron availability and contributes to anemia of chronic disease. At the opposite end are conditions where iron overload leads to serious complications from organ damage. Mutations in HFE gene are the most frequent cause of hereditary hemochromatosis in European population, but rare elsewhere in the world. Iron overload develops in dyserythropoietic anemias from increased intestinal absorption. Transfusional iron overload, most often observed in thalassemia, is increasing among cancer survivors due to the use of protocols requiring intensive transfusion support. Tissue-specific brain iron overload is observed in some degenerative neurological diseases without an increase in systemic iron. New insights into iron metabolism are guiding the development of novel therapies for iron deficiency and iron overload.
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Affiliation(s)
- Ashutosh Lal
- Hematology/Oncology, Department of Pediatrics, University of California, San Francisco, California, USA.
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Vlasveld LT, Janssen R, Bardou-Jacquet E, Venselaar H, Hamdi-Roze H, Drakesmith H, Swinkels DW. Twenty Years of Ferroportin Disease: A Review or An Update of Published Clinical, Biochemical, Molecular, and Functional Features. Pharmaceuticals (Basel) 2019; 12:ph12030132. [PMID: 31505869 PMCID: PMC6789780 DOI: 10.3390/ph12030132] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 08/14/2019] [Accepted: 08/20/2019] [Indexed: 12/14/2022] Open
Abstract
Iron overloading disorders linked to mutations in ferroportin have diverse phenotypes in vivo, and the effects of mutations on ferroportin in vitro range from loss of function (LOF) to gain of function (GOF) with hepcidin resistance. We reviewed 359 patients with 60 ferroportin variants. Overall, macrophage iron overload and low/normal transferrin saturation (TSAT) segregated with mutations that caused LOF, while GOF mutations were linked to high TSAT and parenchymal iron accumulation. However, the pathogenicity of individual variants is difficult to establish due to the lack of sufficiently reported data, large inter-assay variability of functional studies, and the uncertainty associated with the performance of available in silico prediction models. Since the phenotypes of hepcidin-resistant GOF variants are indistinguishable from the other types of hereditary hemochromatosis (HH), these variants may be categorized as ferroportin-associated HH, while the entity ferroportin disease may be confined to patients with LOF variants. To further improve the management of ferroportin disease, we advocate for a global registry, with standardized clinical analysis and validation of the functional tests preferably performed in human-derived enterocytic and macrophagic cell lines. Moreover, studies are warranted to unravel the definite structure of ferroportin and the indispensable residues that are essential for functionality.
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Affiliation(s)
- L Tom Vlasveld
- Department of Internal Medicine, Haaglanden MC-Bronovo, 2597AX The Hague, The Netherlands
| | - Roel Janssen
- Department of Laboratory Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Edouard Bardou-Jacquet
- Liver Diseases Department, French Reference Centre for Rare Iron Overload Diseases of Genetic Origin, University Hospital Pontchaillou, 35033 Rennes, France
| | - Hanka Venselaar
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud, University Medical Center, P.O. Box 9191, 6500 HB Nijmegen, The Netherlands
| | - Houda Hamdi-Roze
- Molecular Genetics Department, French Reference Centre for Rare Iron Overload Diseases of Genetic Origin, University Hospital Pontchaillou, 35033 Rennes, France
| | - Hal Drakesmith
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX39DS, UK
| | - Dorine W Swinkels
- Department of Laboratory Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands.
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Kong X, Xie L, Zhu H, Song L, Xing X, Yang W, Chen X. Genotypic and phenotypic spectra of hemojuvelin mutations in primary hemochromatosis patients: a systematic review. Orphanet J Rare Dis 2019; 14:171. [PMID: 31286966 PMCID: PMC6615163 DOI: 10.1186/s13023-019-1097-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 05/19/2019] [Indexed: 12/12/2022] Open
Abstract
Hereditary hemochromatosis (HH) is a genetic disorder that causes excess absorption of iron and can lead to a variety of complications including liver cirrhosis, arthritis, abnormal skin pigmentation, cardiomyopathy, hypogonadism, and diabetes. Hemojuvelin (HJV) is the causative gene of a rare subtype of HH worldwide. This study aims to systematically review the genotypic and phenotypic spectra of HJV-HH in multiple ethnicities, and to explore the genotype-phenotype correlations. A comprehensive search of PubMed database was conducted. Data were extracted from 57 peer-reviewed original articles including 132 cases with HJV-HH of multiple ethnicities, involving 117 biallelic cases and 15 heterozygotes. Among the biallelic cases, male and female probands of Caucasian ancestry were equally affected, whereas males were more often affected among East Asians (P=1.72×10-2). Hepatic iron deposition and hypogonadism were the most frequently reported complications. Hypogonadism and arthropathy were more prevalent in Caucasians than in East Asians (P=9.30×10-3, 1.69×10-2). Among the recurrent mutations, G320V (45 unrelated cases) and L101P (7 unrelated cases) were detected most frequently and restricted to Caucasians. [Q6H; C321*] was predominant in Chinese patients (6 unrelated cases). I281T (Chinese and Greek), A310G (Brazilian and African American), and R385* (Italian and North African) were reported across different ethnicities. In genotype-phenotype correlation analyses, 91.30% of homozygotes with exon 2-3 mutations developed early-onset HH compared to 66.00% of those with exon 4 mutations (P=2.40×10-2). Hypogonadism occurred more frequently in homozygotes with missense mutations (72.55%) than in those with nonsense mutations (35.71%; P=2.43×10-2). Liver biopsy was accepted by more probands with frame-shift or missense mutations (85.71% and 60.78%, respectively) than by those with nonsense mutations (28.57%; P=2.37×10-2, 3.93×10-2). The present review suggests that patients' ethnicity, geographical region, and genetic predisposition should be considered in the diagnosis, prognosis and management of HJV-HH.
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Affiliation(s)
- Xiaomu Kong
- Department of Endocrinology, China-Japan Friendship Hospital, No. 2 Yinghua East Street, Chaoyang District, Beijing, 100029, China
| | - Lingding Xie
- Department of Endocrinology, China-Japan Friendship Hospital, No. 2 Yinghua East Street, Chaoyang District, Beijing, 100029, China
| | - Haiqing Zhu
- Department of Endocrinology and Metabolism, China Meitan General Hospital, No. 29 Xibahe Nanli, Chaoyang District, Beijing, 100029, China
| | - Lulu Song
- Department of Endocrinology, China-Japan Friendship Hospital, No. 2 Yinghua East Street, Chaoyang District, Beijing, 100029, China
| | - Xiaoyan Xing
- Department of Endocrinology, China-Japan Friendship Hospital, No. 2 Yinghua East Street, Chaoyang District, Beijing, 100029, China
| | - Wenying Yang
- Department of Endocrinology, China-Japan Friendship Hospital, No. 2 Yinghua East Street, Chaoyang District, Beijing, 100029, China
| | - Xiaoping Chen
- Department of Endocrinology, China-Japan Friendship Hospital, No. 2 Yinghua East Street, Chaoyang District, Beijing, 100029, China.
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de Campos WN, Massaro JD, Cançado ELR, Wiezel CEV, Simões AL, Teixeira AC, Souza FFD, Mendes-Junior CT, Martinelli ADLC, Donadi EA. Comprehensive analysis of HFE gene in hereditary hemochromatosis and in diseases associated with acquired iron overload. World J Hepatol 2019; 11:186-198. [PMID: 30820268 PMCID: PMC6393716 DOI: 10.4254/wjh.v11.i2.186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 01/17/2019] [Accepted: 01/26/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Patients with hepatitis C virus (HCV) and hepatocellular carcinoma (HCC) may or not develop iron overload (IO), which is associated with worst prognosis, because can cause serious damage to organs. HFE gene controls the iron uptake from gut, particularly in patients with hereditary hemochromatosis (HH).
AIM To identify associations between HFE coding region in patients exhibiting hereditary hemochromatosis and in diseases associated with acquired IO.
METHODS We sequenced exons 2 to 5 and boundary introns of HFE gene, evaluating all polymorphic sites in patients presenting hereditary (hemochromatosis) or acquired iron overload HCV and HCC) and in healthy controls, using Sanger sequencing. We also determined the ensemble of extended haplotype in healthy control individuals, including several major histocompatibility complex loci, using sequence specific probes. Haplotype reconstruction was performed using the Arlequin and Phase softwares, and linkage disequilibrium (LD) between histocompatibility loci and HFE gene was performed using the Haploview software.
RESULTS The HFE*003 allele was overrepresented (f = 71%) and HFE*001 allele was underrepresented (f = 14%) in HH patients compared to all groups. A strong linkage disequilibrium was observed among the H63D-G, IVS2(+4)-C and C282Y-G gene variants, particularly in HH; however, the mutation IVS2(+4)T>C was not directly associated with HH susceptibility. The HFE*001/HFE*002 genotype conferred susceptibility to HCC in HCV patients exhibiting IO (P = 0.02, OR = 14.14). Although HFE is telomeric to other histocompatibility genes, the H63D-G/IVS2(+4)-C (P ≤ 0.00001/P ≤ 0.0057) combination was in LD with HLA-B*44 allele group in healthy controls. No LD was observed between HFE alleles and other major histocompatibility loci.
CONCLUSION A differential HFE association was observed for HH and for diseases associated with acquired IO (HCV, HCC). Since HFE is very distant from other histocompatibility loci, only weak associations were observed with these alleles.
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Affiliation(s)
- Wagner Narciso de Campos
- Division of Clinical Immunology, Department of Medicine, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14048-900, Brazil
| | - Juliana Doblas Massaro
- Division of Clinical Immunology, Department of Medicine, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14048-900, Brazil
| | - Eduardo Luiz Rachid Cançado
- Department of Gastroenterology, Clinical Gastroenterology and Clinical Hepatology of Clinical Hospital, University of São Paulo School of Medicine, São Paulo 01329-000, Brazil
| | - Cláudia Emília Vieira Wiezel
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14048-900, Brazil
| | - Aguinaldo Luiz Simões
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14048-900, Brazil
| | - Andreza Correa Teixeira
- Division of Gastroenterology, Department of Medicine, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14048-900, Brazil
| | - Fernanda Fernandes de Souza
- Division of Gastroenterology, Department of Medicine, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14048-900, Brazil
| | - Celso Teixeira Mendes-Junior
- Departamento de Química, Laboratório de Pesquisas Forenses e Genômicas, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-901, Brazil
| | - Ana de Lourdes Candolo Martinelli
- Division of Gastroenterology, Department of Medicine, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14048-900, Brazil
| | - Eduardo Antônio Donadi
- Division of Clinical Immunology, Department of Medicine, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14048-900, Brazil
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Choi EK, Nguyen TT, Iwase S, Seo YA. Ferroportin disease mutations influence manganese accumulation and cytotoxicity. FASEB J 2019; 33:2228-2240. [PMID: 30247984 PMCID: PMC6338638 DOI: 10.1096/fj.201800831r] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/27/2018] [Indexed: 12/12/2022]
Abstract
Hemochromatosis is a frequent genetic disorder, characterized by the accumulation of excess iron across tissues. Mutations in the FPN1 gene, encoding a cell surface iron exporter [ferroportin (Fpn)], are responsible for hemochromatosis type 4, also known as ferroportin disease. Recently, Fpn has been implicated in the regulation of manganese (Mn), another essential nutrient required for numerous cellular enzymes. However, the roles of Fpn in Mn regulation remain ill-defined, and the impact of disease mutations on cellular Mn levels is unknown. Here, we provide evidence that Fpn can export Mn from cells into extracellular space. Fpn seems to play protective roles in Mn-induced cellular toxicity and oxidative stress. Finally, disease mutations interfere with the role of Fpn in controlling Mn levels as well as the stability of Fpn. These results define the function of Fpn as an exporter of both iron and Mn and highlight the potential involvement of Mn dysregulation in ferroportin disease.-Choi, E.-K., Nguyen, T.-T., Iwase, S., Seo, Y. A. Ferroportin disease mutations influence manganese accumulation and cytotoxicity.
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Affiliation(s)
- Eun-Kyung Choi
- Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA; and
| | - Trang-Tiffany Nguyen
- Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA; and
| | - Shigeki Iwase
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
| | - Young Ah Seo
- Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA; and
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Measurement of liver iron by magnetic resonance imaging in the UK Biobank population. PLoS One 2018; 13:e0209340. [PMID: 30576354 PMCID: PMC6303057 DOI: 10.1371/journal.pone.0209340] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 12/04/2018] [Indexed: 01/07/2023] Open
Abstract
The burden of liver disease continues to increase in the UK, with liver cirrhosis reported to be the third most common cause of premature death. Iron overload, a condition that impacts liver health, was traditionally associated with genetic disorders such as hereditary haemochromatosis, however, it is now increasingly associated with obesity, type-2 diabetes and non-alcoholic fatty liver disease. The aim of this study was to assess the prevalence of elevated levels of liver iron within the UK Biobank imaging study in a cohort of 9108 individuals. Magnetic resonance imaging (MRI) was undertaken at the UK Biobank imaging centre, acquiring a multi-echo spoiled gradient-echo single-breath-hold MRI sequence from the liver. All images were analysed for liver iron and fat (expressed as proton density fat fraction or PDFF) content using LiverMultiScan. Liver iron was measured in 97.3% of the cohort. The mean liver iron content was 1.32 ± 0.32 mg/g while the median was 1.25 mg/g (min: 0.85 max: 6.44 mg/g). Overall 4.82% of the population were defined as having elevated liver iron, above commonly accepted 1.8 mg/g threshold based on biochemical iron measurements in liver specimens obtained by biopsy. Further analysis using univariate models showed elevated liver iron to be related to male sex (p<10−16, r2 = 0.008), increasing age (p<10−16, r2 = 0.013), and red meat intake (p<10−16, r2 = 0.008). Elevated liver fat (>5.6% PDFF) was associated with a slight increase in prevalence of elevated liver iron (4.4% vs 6.3%, p = 0.0007). This study shows that population studies including measurement of liver iron concentration are feasible, which may in future be used to better inform patient stratification and treatment.
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Dhillon BK, Chopra G, Jamwal M, Chandak GR, Duseja A, Malhotra P, Chawla YK, Garewal G, Das R. Adult onset hereditary hemochromatosis is associated with a novel recurrent Hemojuvelin (HJV) gene mutation in north Indians. Blood Cells Mol Dis 2018; 73:14-21. [DOI: 10.1016/j.bcmd.2018.08.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Revised: 08/23/2018] [Accepted: 08/24/2018] [Indexed: 12/26/2022]
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Ferroportin deficiency in erythroid cells causes serum iron deficiency and promotes hemolysis due to oxidative stress. Blood 2018; 132:2078-2087. [PMID: 30213870 DOI: 10.1182/blood-2018-04-842997] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 09/06/2018] [Indexed: 02/07/2023] Open
Abstract
Ferroportin (FPN), the only known vertebrate iron exporter, transports iron from intestinal, splenic, and hepatic cells into the blood to provide iron to other tissues and cells in vivo. Most of the circulating iron is consumed by erythroid cells to synthesize hemoglobin. Here we found that erythroid cells not only consumed large amounts of iron, but also returned significant amounts of iron to the blood. Erythroblast-specific Fpn knockout (Fpn KO) mice developed lower serum iron levels in conjunction with tissue iron overload and increased FPN expression in spleen and liver without changing hepcidin levels. Our results also showed that Fpn KO mice, which suffer from mild hemolytic anemia, were sensitive to phenylhydrazine-induced oxidative stress but were able to tolerate iron deficiency upon exposure to a low-iron diet and phlebotomy, supporting that the anemia of Fpn KO mice resulted from erythrocytic iron overload and resulting oxidative injury rather than a red blood cell (RBC) production defect. Moreover, we found that the mean corpuscular volume (MCV) values of gain-of-function FPN mutation patients were positively associated with serum transferrin saturations, whereas MCVs of loss-of-function FPN mutation patients were not, supporting that erythroblasts donate iron to blood through FPN in response to serum iron levels. Our results indicate that FPN of erythroid cells plays an unexpectedly essential role in maintaining systemic iron homeostasis and protecting RBCs from oxidative stress, providing insight into the pathophysiology of FPN diseases.
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Phenotypic analysis of hemochromatosis subtypes reveals variations in severity of iron overload and clinical disease. Blood 2018; 132:101-110. [PMID: 29743178 DOI: 10.1182/blood-2018-02-830562] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 05/03/2018] [Indexed: 12/15/2022] Open
Abstract
The clinical progression of HFE-related hereditary hemochromatosis (HH) and its phenotypic variability has been well studied. Less is known about the natural history of non-HFE HH caused by mutations in the HJV, HAMP, or TFR2 genes. The purpose of this study was to compare the phenotypic and clinical presentations of hepcidin-deficient forms of HH. A literature review of all published cases of genetically confirmed HJV, HAMP, and TFR2 HH was performed. Phenotypic and clinical data from a total of 156 patients with non-HFE HH was extracted from 53 publications and compared with data from 984 patients with HFE-p.C282Y homozygous HH from the QIMR Berghofer Hemochromatosis Database. Analyses confirmed that non-HFE forms of HH have an earlier age of onset and a more severe clinical course than HFE HH. HJV and HAMP HH are phenotypically and clinically very similar and have the most severe presentation, with cardiomyopathy and hypogonadism being particularly prevalent findings. TFR2 HH is more intermediate in its age of onset and severity. All clinical outcomes analyzed were more prevalent in the juvenile forms of HH, with the exception of arthritis and arthropathy, which were more commonly seen in HFE HH. This is the first comprehensive analysis comparing the different phenotypic and clinical aspects of the genetic forms of HH, and the results will be valuable for the differential diagnosis and management of these conditions. Importantly, our analyses indicate that factors other than iron overload may be contributing to joint pathology in patients with HFE HH.
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Raju K, Venkataramappa SM. Primary Hemochromatosis Presenting as Type 2 Diabetes Mellitus: A Case Report with Review of Literature. Int J Appl Basic Med Res 2018; 8:57-60. [PMID: 29552540 PMCID: PMC5846224 DOI: 10.4103/ijabmr.ijabmr_402_16] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Hemochromatosis is an autosomal recessive genetic disorder resulting in increased intestinal absorption of iron and eventually to iron overload. The onset of symptoms is usually seen around 40 years of age. Iron overload causes tissue damage in liver, pancreas, skin, joints, heart, and gonads. Approximately 50% of patients diagnosed with hemochromatosis will have either type 1 or type 2 diabetes mellitus (DM) because of selective beta-cell damage due to iron overload and leads to impaired insulin synthesis, release, and insulin resistance. Early diagnosis and treatment of hemochromatosis prevents the development of diabetes. We present a case in a 48-year-old male with a history of DM for 6 months and skin pigmentation over face for 1 year.
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Affiliation(s)
- Kalyani Raju
- Department of Pathology, Sri Devaraj Urs Medical College, Sri Devaraj Urs Academy of Higher Education and Research, Kolar, India
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Structure-function analysis of ferroportin defines the binding site and an alternative mechanism of action of hepcidin. Blood 2017; 131:899-910. [PMID: 29237594 DOI: 10.1182/blood-2017-05-786590] [Citation(s) in RCA: 210] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 11/30/2017] [Indexed: 02/07/2023] Open
Abstract
Nonclassical ferroportin disease (FD) is a form of hereditary hemochromatosis caused by mutations in the iron transporter ferroportin (Fpn), resulting in parenchymal iron overload. Fpn is regulated by the hormone hepcidin, which induces Fpn endocytosis and cellular iron retention. We characterized 11 clinically relevant and 5 nonclinical Fpn mutations using stably transfected, inducible isogenic cell lines. All clinical mutants were functionally resistant to hepcidin as a consequence of either impaired hepcidin binding or impaired hepcidin-dependent ubiquitination despite intact hepcidin binding. Mapping the residues onto 2 computational models of the human Fpn structure indicated that (1) mutations that caused ubiquitination-resistance were positioned at helix-helix interfaces, likely preventing the hepcidin-induced conformational change, (2) hepcidin binding occurred within the central cavity of Fpn, (3) hepcidin interacted with up to 4 helices, and (4) hepcidin binding should occlude Fpn and interfere with iron export independently of endocytosis. We experimentally confirmed hepcidin-mediated occlusion of Fpn in the absence of endocytosis in multiple cellular systems: HEK293 cells expressing an endocytosis-defective Fpn mutant (K8R), Xenopus oocytes expressing wild-type or K8R Fpn, and mature human red blood cells. We conclude that nonclassical FD is caused by Fpn mutations that decrease hepcidin binding or hinder conformational changes required for ubiquitination and endocytosis of Fpn. The newly documented ability of hepcidin and its agonists to occlude iron transport may facilitate the development of broadly effective treatments for hereditary iron overload disorders.
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Kawabata H. The mechanisms of systemic iron homeostasis and etiology, diagnosis, and treatment of hereditary hemochromatosis. Int J Hematol 2017; 107:31-43. [PMID: 29134618 DOI: 10.1007/s12185-017-2365-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Accepted: 11/08/2017] [Indexed: 02/06/2023]
Abstract
Hereditary hemochromatosis (HH) is a group of genetic iron overload disorders that manifest with various symptoms, including hepatic dysfunction, diabetes, and cardiomyopathy. Classic HH type 1, which is common in Caucasians, is caused by bi-allelic mutations of HFE. Severe types of HH are caused by either bi-allelic mutations of HFE2 that encodes hemojuvelin (type 2A) or HAMP that encodes hepcidin (type 2B). HH type 3, which is of intermediate severity, is caused by bi-allelic mutations of TFR2 that encodes transferrin receptor 2. Mutations of SLC40A1 that encodes ferroportin, the only cellular iron exporter, causes either HH type 4A (loss-of-function mutations) or HH type 4B (gain-of-function mutations). Studies on these gene products uncovered a part of the mechanisms of the systemic iron regulation; HFE, hemojuvelin, and TFR2 are involved in iron sensing and stimulating hepcidin expression, and hepcidin downregulates the expression of ferroportin of the target cells. Phlebotomy is the standard treatment for HH, and early initiation of the treatment is essential for preventing irreversible organ damage. However, because of the rarity and difficulty in making the genetic diagnosis, a large proportion of patients with non-HFE HH might have been undiagnosed; therefore, awareness of this disorder is important.
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Affiliation(s)
- Hiroshi Kawabata
- Department of Hematology and Immunology, Kanazawa Medical University, 1-1 Daigaku, Uchinada-machi, Ishikawa-ken, 920-0293, Japan.
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Pietrangelo A. Ferroportin disease: pathogenesis, diagnosis and treatment. Haematologica 2017; 102:1972-1984. [PMID: 29101207 PMCID: PMC5709096 DOI: 10.3324/haematol.2017.170720] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 09/25/2017] [Indexed: 12/14/2022] Open
Abstract
Ferroportin Disease (FD) is an autosomal dominant hereditary iron loading disorder associated with heterozygote mutations of the ferroportin-1 (FPN) gene. It represents one of the commonest causes of genetic hyperferritinemia, regardless of ethnicity. FPN1 transfers iron from the intestine, macrophages and placenta into the bloodstream. In FD, loss-of-function mutations of FPN1 limit but do not impair iron export in enterocytes, but they do severely affect iron transfer in macrophages. This leads to progressive and preferential iron trapping in tissue macrophages, reduced iron release to serum transferrin (i.e. inappropriately low transferrin saturation) and a tendency towards anemia at menarche or after intense bloodletting. The hallmark of FD is marked iron accumulation in hepatic Kupffer cells. Numerous FD-associated mutations have been reported worldwide, with a few occurring in different populations and some more commonly reported (e.g. Val192del, A77D, and G80S). FPN1 polymorphisms also represent the gene variants most commonly responsible for hyperferritinemia in Africans. Differential diagnosis includes mainly hereditary hemochromatosis, the syndrome commonly due to either HFE or TfR2, HJV, HAMP, and, in rare instances, FPN1 itself. Here, unlike FD, hyperferritinemia associates with high transferrin saturation, iron-spared macrophages, and progressive parenchymal cell iron load. Abdominal magnetic resonance imaging (MRI), the key non-invasive diagnostic tool for the diagnosis of FD, shows the characteristic iron loading SSL triad (spleen, spine and liver). A non-aggressive phlebotomy regimen is recommended, with careful monitoring of transferrin saturation and hemoglobin due to the risk of anemia. Family screening is mandatory since siblings and offspring have a 50% chance of carrying the pathogenic mutation.
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Affiliation(s)
- Antonello Pietrangelo
- Center for Hemochromatosis, Department of Internal Medicine II, University of Modena and Reggio Emilia Policlinico, Modena, Italy
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31
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Ramzan K, Imtiaz F, Al-Ashgar HI, AlSayed M, Sulaiman RA. Juvenile hemochromatosis and hepatocellular carcinoma in a patient with a novel mutation in the HJV gene. Eur J Med Genet 2017; 60:308-311. [DOI: 10.1016/j.ejmg.2017.03.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 03/09/2017] [Accepted: 03/11/2017] [Indexed: 02/06/2023]
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Heath KM, Axton JH, McCullough JM, Harris N. Reply to Delanghe, Speeckaert, and De Buyzere: "The evolutionary adaptation of hemochromatosis associated mutations during the Neolithic". AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2016; 161:532-533. [PMID: 27393296 DOI: 10.1002/ajpa.23047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 06/17/2016] [Indexed: 11/06/2022]
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Delanghe JR, Speeckaert MM, De Buyzere ML. The evolutionary adaptation of hemochromatosis associated mutations during the neolithic. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2016; 161:530-531. [PMID: 27348451 DOI: 10.1002/ajpa.23045] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 06/12/2016] [Indexed: 11/07/2022]
Affiliation(s)
- Joris R Delanghe
- Department of Clinical chemistry, Ghent University, Ghent, Belgium.
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Abstract
Iron is an essential element for several metabolic pathways and physiological processes. The maintenance of iron homeostasis within the human body requires a dynamic and highly sophisticated interplay of several proteins, as states of iron deficiency or excess are both potentially deleterious to health. Among these is plasma transferrin, which is central to iron metabolism not only through iron transport between body tissues in a soluble nontoxic form but also through its protective scavenger role in sequestering free toxic iron. The transferrin saturation (TSAT), an index that takes into account both plasma iron and its main transport protein, is considered an important biochemical marker of body iron status. Its increasing use in many health systems is due to the increased availability of measurement methods, such as calorimetry, turbidimetry, nephelometry, and immunochemistry to estimate its value. However, despite its frequent use in clinical practice to detect states of iron deficiency or iron overload, careful attention should be paid to the inherent limitations of the test especially in certain settings such as inflammation in order to avoid misinterpretation and erroneous conclusions. Beyond its usual clinical use, an emerging body of evidence has linked TSAT levels to major clinical outcomes such as cardiovascular mortality. This has the potential to extend the utility of TSAT index to risk stratification and prognostication. However, most of the current evidence is mainly driven by observational studies where the risk of residual confounding cannot be fully eliminated. Indeed, future efforts are required to fully explore this capability in well-designed clinical trials or prospective large-scale cohorts.
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Affiliation(s)
- M E Elsayed
- Graduate Entry Medical School, University of Limerick, Limerick, Ireland; University Hospital Limerick, Limerick, Ireland
| | - M U Sharif
- Graduate Entry Medical School, University of Limerick, Limerick, Ireland; University Hospital Limerick, Limerick, Ireland
| | - A G Stack
- Graduate Entry Medical School, University of Limerick, Limerick, Ireland; University Hospital Limerick, Limerick, Ireland; Health Research Institute, University of Limerick, Limerick, Ireland.
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35
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Porto G, Brissot P, Swinkels DW, Zoller H, Kamarainen O, Patton S, Alonso I, Morris M, Keeney S. EMQN best practice guidelines for the molecular genetic diagnosis of hereditary hemochromatosis (HH). Eur J Hum Genet 2016; 24:479-95. [PMID: 26153218 PMCID: PMC4929861 DOI: 10.1038/ejhg.2015.128] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 04/29/2015] [Accepted: 05/06/2015] [Indexed: 12/14/2022] Open
Abstract
Molecular genetic testing for hereditary hemochromatosis (HH) is recognized as a reference test to confirm the diagnosis of suspected HH or to predict its risk. The vast majority (typically >90%) of patients with clinically characterized HH are homozygous for the p.C282Y variant in the HFE gene, referred to as HFE-related HH. Since 1996, HFE genotyping was implemented in diagnostic algorithms for suspected HH, allowing its early diagnosis and prevention. However, the penetrance of disease in p.C282Y homozygotes is incomplete. Hence, homozygosity for p.C282Y is not sufficient to diagnose HH. Neither is p.C282Y homozygosity required for diagnosis as other rare forms of HH exist, generally referred to as non-HFE-related HH. These pose significant challenges when defining criteria for referral, testing protocols, interpretation of test results and reporting practices. We present best practice guidelines for the molecular genetic diagnosis of HH where recommendations are classified, as far as possible, according to the level and strength of evidence. For clarification, the guidelines' recommendations are preceded by a detailed description of the methodology and results obtained with a series of actions taken in order to achieve a wide expert consensus, namely: (i) a survey on the current practices followed by laboratories offering molecular diagnosis of HH; (ii) a systematic literature search focused on some identified controversial topics; (iii) an expert Best Practice Workshop convened to achieve consensus on the practical recommendations included in the guidelines.
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Affiliation(s)
- Graça Porto
- Center for Predictive and Preventive Genetics (CGPP), Institute of Molecular and Cellular Biology (IBMC), Porto, Portugal
- Clinical Haematology, Hospital Santo António (CHP-HAS) and Department of Molecular Pathology and Immunology, Abel Salazar Institute for Biomedical Sciences (ICBAS), University of Porto, Porto, Portugal
| | - Pierre Brissot
- Liver Disease Unit, Pontchaillou University Hospital, University of Rennes, and National Reference Centre for Rare Iron Overload Diseases of Genetic Origin, Rennes, France
| | - Dorine W Swinkels
- Department of Laboratory Medicine, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Heinz Zoller
- Department of Medicine II, Gastroenterology and Hepatology, Medical University of Innsbruck, Innsbruck, Austria
| | | | - Simon Patton
- European Molecular Quality Network (EMQN), Manchester, UK
| | - Isabel Alonso
- Center for Predictive and Preventive Genetics (CGPP), Institute of Molecular and Cellular Biology (IBMC), Porto, Portugal
| | - Michael Morris
- European Molecular Quality Network (EMQN), Manchester, UK
- Synlab, Lausanne, Switzerland
| | - Steve Keeney
- European Molecular Quality Network (EMQN), Manchester, UK
- Molecular Diagnostics Centre (Haematology), Manchester Royal Infirmary, Manchester, UK
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36
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Das R, Ahluwalia J, Sachdeva MUS. Hematological Practice in India. Hematol Oncol Clin North Am 2016; 30:433-44. [DOI: 10.1016/j.hoc.2015.11.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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37
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Fonseca PFS, Cançado RD, Uellendahl Lopes MM, Correia E, Lescano MA, Santos PCJL. HAMP Gene Mutation Associated with Juvenile Hemochromatosis in Brazilian Patients. Acta Haematol 2016; 135:228-31. [PMID: 27007796 DOI: 10.1159/000444119] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 01/17/2016] [Indexed: 12/15/2022]
Affiliation(s)
- Paula Fernanda Silva Fonseca
- Laboratory of Genetics and Molecular Cardiology, Heart Institute (InCor), University of Sx00E3;o Paulo Medical School, Sx00E3;o Paulo, Brazil
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38
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Analysis of Familial Tendencies in Transferrin Saturation in a Korean Population. Dig Dis Sci 2015; 60:3136-41. [PMID: 26003557 DOI: 10.1007/s10620-015-3720-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 05/13/2015] [Indexed: 12/09/2022]
Abstract
BACKGROUND Despite the high transferrin saturation (TS) level in Koreans, the p.Cys282Tyr and p.His63Asp mutations are markedly less frequent than in Caucasians. We aimed to determine TS levels and their familial tendencies in a Korean population using nationwide data from the Fifth Korea National Health and Nutrition Examination Survey (KNHANES V-1 2010). METHODS A total of 4904 subjects without a history of hepatitis B and C virus infection, or liver cirrhosis, and who were negative for anemia and hepatitis B antigen were enrolled. A familial tendency analysis was performed in 260 families. Parents were grouped into four quartiles based on their TS levels. Offspring were categorized according to the mean parental TS four quartile scores (1.0, 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0). A familial tendency was evaluated by comparing the mean TS of offspring in seven parental groups. RESULTS The mean TS was 39.3 ± 15.6% for Korean males and 33.2 ± 12.9% for Korean females, and both were significantly higher than those of Caucasians reported in the HEIRS study (30.6 ± 11.0% for male, 25.6 ± 10.6% for female, P < 0.001). The 260 families showed statistically significant familial tendencies of TS values (P < 0.001). The mean TS of offspring in parental group 1.0, 1.5, 2.0, and 2.5 showed a lower value than that in higher group 3.0, 3.5, and 4.0. In contrast, there were no significant differences in age, daily dietary iron intake, and AST or ALT value among seven groups. CONCLUSIONS These findings suggest unidentified genetic variations on high TS in Koreans beyond the p.Cys282Tyr and p.His63Asp mutations commonly identified in Caucasians.
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Healey EG, Bishop B, Elegheert J, Bell CH, Padilla-Parra S, Siebold C. Repulsive guidance molecule is a structural bridge between neogenin and bone morphogenetic protein. Nat Struct Mol Biol 2015; 22:458-65. [PMID: 25938661 PMCID: PMC4456160 DOI: 10.1038/nsmb.3016] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 03/31/2015] [Indexed: 02/07/2023]
Abstract
Repulsive guidance molecules (RGMs) control crucial processes including cell motility, adhesion, immune-cell regulation and systemic iron metabolism. RGMs signal via the neogenin (NEO1) and the bone morphogenetic protein (BMP) pathways. Here, we report crystal structures of the N-terminal domains of all human RGM family members in complex with the BMP ligand BMP2, revealing a new protein fold and a conserved BMP-binding mode. Our structural and functional data suggest a pH-linked mechanism for RGM-activated BMP signaling and offer a rationale for RGM mutations causing juvenile hemochromatosis. We also determined the crystal structure of the ternary BMP2-RGM-NEO1 complex, which, along with solution scattering and live-cell super-resolution fluorescence microscopy, indicates BMP-induced clustering of the RGM-NEO1 complex. Our results show how RGM acts as the central hub that links BMP and NEO1 and physically connects these fundamental signaling pathways.
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Affiliation(s)
- Eleanor G Healey
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Benjamin Bishop
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Jonathan Elegheert
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Christian H Bell
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Sergi Padilla-Parra
- 1] Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK. [2] Cellular Imaging Core, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Christian Siebold
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
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40
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Gichohi-Wainaina WN, Melse-Boonstra A, Swinkels DW, Zimmermann MB, Feskens EJ, Towers GW. Common Variants and Haplotypes in the TF, TNF-α, and TMPRSS6 Genes Are Associated with Iron Status in a Female Black South African Population. J Nutr 2015; 145:945-53. [PMID: 25809685 DOI: 10.3945/jn.114.209148] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 03/10/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND It is unknown whether single nucleotide polymorphisms (SNPs), associated with iron status in European and Asian populations, have the same relation within the African population. OBJECTIVES We investigated associations of reported SNPs with iron markers in a South African cohort. METHODS Hemoglobin concentration, serum ferritin (SF) and soluble transferrin receptor (sTfR) concentrations, and body iron (BI) stores were measured in women (n = 686; range, 32-86 y) who were part of the Prospective Urban and Rural Epidemiology study. Thirty-two SNPs in 12 genes were selected based on existing genome-wide association study data. RESULTS In the transferrin (TF) gene, SF and BI were significantly lower in the heterozygote genotype (AG) of reference SNP (rs) 1799852 (P = 0.01 and 0.03, respectively) and sTfR concentrations were significantly higher (P = 0.004) than the homozygote minor allele genotype (AA), whereas transferrin receptor and BI concentrations were significantly lower in the heterozygote genotype (AG) of rs3811647 (both P = 0.03) than the homozygote wild-type (AA) and minor allele groups (GG). The chromosome 6 allele combination (AAA) consisting of rs1799964 and rs1800629 both in tumor necrosis factor-α (TNF-α) and rs2071592 in nuclear factor κB inhibitor-like protein 1 (NFKBIL1) was associated with higher odds for low SF concentrations (SF < 15 μg/L; OR: 1.86; 95% CI: 1.23, 2.79) than the allele combinations AGA, GGT, and AGT. The chromosome 22 allele combination (GG) consisting of rs228918 and rs228921 in the transmembrane protease serine 6 (TMPRSS6) gene was associated with lower odds for increased sTfR concentrations (sTfR > 8.3mg/L; OR: 0.79; 95% CI: 0.63, 0.98) than the allele combination AA. CONCLUSIONS Various SNPs and allele combinations in the TF, TNF-α, and TMPRSS6 genes are associated with iron status in black South African women; however, these association patterns are different compared with European ancestry populations. This stresses the need for population-specific genomic data.
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Affiliation(s)
| | - Alida Melse-Boonstra
- Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands;
| | - Dorine W Swinkels
- The Laboratory of Genetic, Endocrine, and Metabolic Diseases, Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Michael B Zimmermann
- Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands; Laboratory of Human Nutrition, Institute of Food Nutrition and Health, Department of Health Sciences and Technology, Swiss Federal Institute of Technology, Zurich, Switzerland; and
| | - Edith J Feskens
- Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands
| | - G Wayne Towers
- Center of Excellence for Nutrition, North-West University, Potchefstroom, South Africa
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Neřoldová M, Fraňková S, Stránecký V, Honsová E, Lukšan O, Beneš M, Michalová K, Kmoch S, Jirsa M. Hereditary haemochromatosis caused by homozygous HJV mutation evolved through paternal disomy. Clin Genet 2014; 87:96-8. [PMID: 24635876 DOI: 10.1111/cge.12346] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 01/07/2014] [Accepted: 01/10/2014] [Indexed: 11/30/2022]
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42
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Brissot P, Bardou-Jacquet E, Troadec MB, Mosser A, Island ML, Detivaud L, Loréal O, Jouanolle AM. Molecular diagnosis of genetic iron-overload disorders. Expert Rev Mol Diagn 2014; 10:755-63. [DOI: 10.1586/erm.10.55] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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43
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Morris EA, Rees GG, Gorard DA. Hereditary haemochromatosis in a man of Pakistani descent. QJM 2013; 106:1031-3. [PMID: 22328543 DOI: 10.1093/qjmed/hcs018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- E A Morris
- Wycombe Hospital, Queen Alexandra Road, High Wycombe, Bucks HP11 2TT, UK.
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44
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McDonald CJ, Wallace DF, Crawford DHG, Subramaniam VN. Iron storage disease in Asia-Pacific populations: the importance of non-HFE mutations. J Gastroenterol Hepatol 2013; 28:1087-94. [PMID: 23577916 DOI: 10.1111/jgh.12222] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/03/2013] [Indexed: 01/24/2023]
Abstract
Hereditary hemochromatosis (HH) is a widely recognized and well-studied condition in European populations. This is largely due to the high prevalence of the C282Y mutation of HFE. Although less common than in Europe, HH cases have been reported in the Asia-Pacific region because of mutations in both HFE and non-HFE genes. Mutations in all of the currently known genes implicated in non-HFE HH (hemojuvelin, hepcidin, transferrin receptor 2, and ferroportin) have been reported in patients from the Asia-Pacific region. This review discusses the molecular basis of HH and the genes and mutations known to cause non-HFE HH with particular reference to the Asia-Pacific region. Challenges in the genetic diagnosis of non-HFE HH are also discussed and how new technologies such as next generation sequencing may be informative in the future.
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Affiliation(s)
- Cameron J McDonald
- The Membrane Transport Laboratory, The Queensland Institute of Medical Research, Brisbane, Queensland, Australia
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45
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Taher AT, Porter JB, Viprakasit V, Kattamis A, Chuncharunee S, Sutcharitchan P, Siritanaratkul N, Galanello R, Karakas Z, Lawniczek T, Habr D, Ros J, Zhang Y, Cappellini MD. Deferasirox demonstrates a dose-dependent reduction in liver iron concentration and consistent efficacy across subgroups of non-transfusion-dependent thalassemia patients. Am J Hematol 2013; 88:503-6. [PMID: 23553596 PMCID: PMC3698696 DOI: 10.1002/ajh.23445] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 03/19/2013] [Accepted: 03/22/2013] [Indexed: 01/24/2023]
Abstract
The 1-year THALASSA study enrolled 166 patients with various non-transfusion-dependent thalassemia (NTDT) syndromes, degrees of iron burden and patient characteristics, and demonstrated the overall efficacy and safety of deferasirox in reducing liver iron concentration (LIC) in these patients. Here, reduction in LIC with deferasirox 5 and 10 mg/kg/day starting dose groups is shown to be consistent across the following patient subgroups—baseline LIC/serum ferritin, age, gender, race, splenectomy (yes/no), and underlying NTDT syndrome (β-thalassemia intermedia, HbE/β-thalassemia or α-thalassemia). These analyses also evaluated deferasirox dosing strategies for patients with NTDT. Greater reductions in LIC were achieved in patients dose-escalated at Week 24 from deferasirox 10 mg/kg/day starting dose to 20 mg/kg/day. Patients who received an average actual dose of deferasirox >12.5–≤17.5 mg/kg/day achieved a greater LIC decrease compared with the ≥7.5–≤12.5 mg/kg/day and >0–<7.5 mg/kg/day subgroups, demonstrating a dose–response efficacy. LIC reduction across patient subgroups was generally consistent with the primary efficacy analysis with a similar safety profile. Am. J. Hematol. 88:503–506, 2013. © 2013 Wiley Periodicals, Inc.
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Affiliation(s)
- Ali T. Taher
- Hematology and Oncology, Department of Internal Medicine, American University of BeirutBeirut Lebanon
| | - John B. Porter
- UCL Cancer Institute, Department of Haematology, University College LondonLondon United Kingdom
| | - Vip Viprakasit
- Department of Pediatrics and Internal MedicineSiriraj Hospital, Mahidol UniversityBangkok Thailand
| | | | | | - Pranee Sutcharitchan
- Chulalongkorn University and King Chulalongkorn Memorial HospitalBangkok Thailand
| | - Noppadol Siritanaratkul
- Department of Pediatrics and Internal MedicineSiriraj Hospital, Mahidol UniversityBangkok Thailand
| | | | - Zeynep Karakas
- Istanbul University, Istanbul Medical FacultyIstanbul Turkey
| | | | - Dany Habr
- Novartis PharmaceuticalsEast Hanover New Jersey
| | | | - Yiyun Zhang
- Novartis PharmaceuticalsEast Hanover New Jersey
| | - M. Domenica Cappellini
- Department of Internal Medicine, Università di Milano, Ca Granda Foundation IRCCSMilan Italy
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Nekhai S, Xu M, Foster A, Kasvosve I, Diaz S, Machado RF, Castro OL, Kato GJ, Taylor JG, Gordeuk VR. Reduced sensitivity of the ferroportin Q248H mutant to physiological concentrations of hepcidin. Haematologica 2012; 98:455-63. [PMID: 23065513 DOI: 10.3324/haematol.2012.066530] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Ferroportin Q248H mutation has an allele frequency of 2.2-13.4% in African populations and is associated with a mild tendency to increased serum ferritin in the general population. Some investigators have reported that ferroportin Q248H is degraded after exposure to hepcidin in exactly the same manner as wild-type ferroportin, but supraphysiological concentrations of hepcidin were used. The aim of our study was to determine whether ferroportin Q248H may have reduced sensitivity to physiological concentrations of hepcidin. The sensitivity of ferroportin Q248H to hepcidin was determined in 293T cells transiently expressing ferroportin using immunoblotting and fluorescence analysis. Ferritin concentrations were measured in these cells and also in human primary monocytes derived from humans with different ferroportin genotypes. The effect of Q248H on serum iron measures was examined in patients with sickle cell anemia. Immunoblotting and fluorescence analysis showed decreased sensitivity of ferroportin Q248H to physiological concentrations of hepcidin. Lower ferritin concentrations were observed after incubation with iron and hepcidin in 293T cells expressing ferroportin Q248H and in primary monocytes from ferroportin Q248H subjects. In sickle cell anemia, ferroportin Q248H heterozygotes had lower serum ferritin concentrations than wild-type subjects, consistent with enhanced iron release by macrophage ferroportin Q248H. A clinical benefit of ferroportin Q248H was suggested by lower echocardiographic estimates of pulmonary artery pressure in patients carrying mutant alleles. In conclusion, our results suggest that ferroportin Q248H protein is resistant to physiological concentrations of hepcidin and that this mutation has discernible effects on iron metabolism-related clinical complications of sickle cell anemia. They provide a mechanistic explanation for the effect of ferroportin Q248H on iron status in individuals of African descent and suggest that these changes in iron metabolism may be beneficial under certain disease-specific circumstances. (ClinicalTrials.gov Identifier:NCT00011648).
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Affiliation(s)
- Sergei Nekhai
- Center for Sickle Cell Disease, Department of Medicine, Howard University, Washington, DC, USA.
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Santos PCJDL, Dinardo CL, Cançado RD, Schettert IT, Krieger JE, Pereira AC. Non-HFE hemochromatosis. Rev Bras Hematol Hemoter 2012; 34:311-6. [PMID: 23049448 PMCID: PMC3460409 DOI: 10.5581/1516-8484.20120079] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 07/10/2012] [Indexed: 12/15/2022] Open
Abstract
Hereditary hemochromatosis (HH) is an autosomal recessive disorder classically related to HFE mutations. However, since 1996, it is known that HFE mutations explain about 80% of HH cases, with the remaining around 20% denominated non-HFE hemochromatosis. Nowadays, four main genes are implicated in the pathophysiology of clinical syndromes classified as non-HFE hemochromatosis: hemojuvelin (HJV, type 2Ajuvenile HH), hepcidin (HAMP, type 2B juvenile HH), transferrin receptor 2 (TFR2, type 3 HH) and ferroportin (SLC40A1, type 4 HH). The aim of this review is to explore molecular, clinical and management aspects of non-HFE hemochromatosis.
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Hattori A, Tomosugi N, Tatsumi Y, Suzuki A, Hayashi K, Katano Y, Inagaki Y, Ishikawa T, Hayashi H, Goto H, Wakusawa S. Identification of a novel mutation in the HAMP gene that causes non-detectable hepcidin molecules in a Japanese male patient with juvenile hemochromatosis. Blood Cells Mol Dis 2012; 48:179-82. [DOI: 10.1016/j.bcmd.2012.01.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 12/29/2011] [Accepted: 12/30/2011] [Indexed: 10/14/2022]
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Molecular diagnostic and pathogenesis of hereditary hemochromatosis. Int J Mol Sci 2012; 13:1497-1511. [PMID: 22408404 PMCID: PMC3291973 DOI: 10.3390/ijms13021497] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 01/12/2012] [Accepted: 01/13/2012] [Indexed: 12/15/2022] Open
Abstract
Hereditary hemochromatosis (HH) is an autosomal recessive disorder characterized by enhanced intestinal absorption of dietary iron. Without therapeutic intervention, iron overload leads to multiple organ damage such as liver cirrhosis, cardiomyopathy, diabetes, arthritis, hypogonadism and skin pigmentation. Most HH patients carry HFE mutant genotypes: homozygosity for p.Cys282Tyr or p.Cys282Tyr/p.His63Asp compound heterozygosity. In addition to HFE gene, mutations in the genes that encode hemojuvelin (HJV), hepcidin (HAMP), transferrin receptor 2 (TFR2) and ferroportin (SLC40A1) have been associated with regulation of iron homeostasis and development of HH. The aim of this review was to identify the main gene mutations involved in the pathogenesis of type 1, 2, 3 and 4 HH and their genetic testing indication. HFE testing for the two main mutations (p.Cys282Tyr and p.His63Asp) should be performed in all patients with primary iron overload and unexplained increased transferrin saturation and/or serum ferritin values. The evaluation of the HJV p.Gly320Val mutation must be the molecular test of choice in suspected patients with juvenile hemochromatosis with less than 30 years and cardiac or endocrine manifestations. In conclusion, HH is an example that genetic testing can, in addition to performing the differential diagnostic with secondary iron overload, lead to more adequate and faster treatment.
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