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Singal M, Mahmoud A, Phatak PD. Clinical characteristics of HFE C282Y/H63D compound heterozygotes identified in a specialty practice: key differences from HFE C282Y homozygotes. Expert Rev Hematol 2024; 17:145-152. [PMID: 38551816 DOI: 10.1080/17474086.2024.2337950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 02/13/2024] [Indexed: 04/04/2024]
Abstract
BACKGROUND Patients with p.C282Y homozygous (p.C282Y) HFE mutations are more likely to develop hemochromatosis (HC) than p.C282Y/p.H63D compound heterozygotes (p.C282Y/H63D). RESEARCH DESIGN AND METHODS We conducted a retrospective chart review of 90 p.C282Y and 31 p.C282Y/H63D patients at a referral practice to illustrate the differences in the natural history of the disease in these two HC cohorts. RESULTS Over a median follow-up of 17 years, p.C282Y had higher mean serum ferritin (1105 mg/dL vs. 534 mg/dL, p = 0.001) and transferrin saturations (75.3% vs. 49.5%, p = 0.001) at diagnosis. p.C282Y underwent more therapeutic phlebotomies (TP) till de-ironing (mean 24 vs. 10), had higher mean mobilized iron stores (4759 mg vs. 1932 mg), and required more annual maintenance TP (1.9/year vs. 1.1/year, p = 0.039). p.C282Y/H63D were more likely to have obesity (45.2% vs. 20.2%, p = 0.007) at diagnosis, with a non-significant trend toward consuming more alcohol. There was no significant difference in the development of HC-related complications between the two cohorts. CONCLUSIONS p.C282Y have a higher mobilizable iron and require more TP. p.C282Y/H63D likely require additional insults such as obesity or alcohol use to develop elevated ferritin. De-ironing may mitigate the risk of developing HC-related complications.
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Affiliation(s)
- Mukul Singal
- Hematology and Oncology, Rochester General Hospital, Rochester, NY, USA
- Department of Internal Medicine, Rochester General Hospital, Rochester, NY, USA
| | - Amir Mahmoud
- Internal Medicine Residency Program, Rochester General Hospital, Rochester, NY, USA
| | - Pradyumna Dinkar Phatak
- Hematology and Oncology, Rochester General Hospital, Rochester, NY, USA
- Department of Internal Medicine, Rochester General Hospital, Rochester, NY, USA
- Internal Medicine Residency Program, Rochester General Hospital, Rochester, NY, USA
- Mary M Gooley Hemophilia Center, Rochester, NY, USA
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Gadallah ANAA, Atti EAA, Salman TAH, Hassan AEO, Bedair HM. Predictive Role for Serum Aldo-Keto Reductase Family1 Member B10 for Early Detection of Hepatocellular Carcinoma in Egyptian Patients. Open Access Maced J Med Sci 2022. [DOI: 10.3889/oamjms.2022.7149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Background: Most patients with hepatocellular carcinoma (HCC) are diagnosed at late stages despite of improvement screening programs and lack of effective diagnostic methods for cases with preclinical HCC leads to a low rate of early detection. Aldo-keto reductase family 1 member B10 (AKR1B10) is associated with several types of cancer. However, to our knowledge, the diagnostic significance of AKR1B10 measurement in early stage of HCC has poorly understood.
Aim
To evaluate the diagnostic performance of serum AKR1B10 in hepatitis C virus (HCV)-related liver disorders and its unique role in diagnosing HCC.
Methods
Serum AKR1B10 was detected by sandwich ELISA in 30 patients with HCV-related HCC, 30 patients with HCV related liver cirrhosis, and 20 healthy controls. Both Serum AKR1B10 and α-fetoprotein (AFP) levels were analyzed, evaluated and compared.
Results
Serum AKR1B10 was significantly elevated in patients with HCC compared with. The sensitivity (86.7.0%) and specificity (70%) for HCC diagnosis with AKR1B10 were high at a cutoff value of 0.945 ng/ml, while alpha fetoprotein had sensitivity 67% and specificity 88% in early detection of HCC among studied groups at cutoff point higher than 17.9. ng/ml. Furthermore, concurrent measurement of Alpha fetoprotein and AKR1B10 had increased sensitivity to 97.6% and specificity 100% in early detection of HCC among studied groups at cutoff point higher than ≥150 ng/ml. Furthermore, concurrent measurement of serum AKR1B10 and AFP significantly increased sensitivity and negative predictive value for HCC diagnosis.
Conclusions
we concluded in the current study that AKR1B10 has a unique role as a biomarker for early-stage HCV-related HCC. Compared with AFP alone, a combination of serum AKR1B10 and AFP had an increased the diagnostic performance in patients with HCC.
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Ceruloplasmin gene variants are associated with hyperferritinemia and increased liver iron in patients with NAFLD. J Hepatol 2021; 75:506-513. [PMID: 33774058 DOI: 10.1016/j.jhep.2021.03.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 03/03/2021] [Accepted: 03/10/2021] [Indexed: 12/13/2022]
Abstract
BACKGROUND & AIMS Non-alcoholic fatty liver disease (NAFLD) is a multifactorial disorder resulting from genetic and environmental factors. Hyperferritinemia has been associated with increased hepatic iron stores and worse outcomes in patients with NAFLD. The aim of this study was to evaluate the prevalence of variants of iron-related genes and their association with hyperferritinemia, hepatic iron stores and liver disease severity in patients with NAFLD. METHODS From a cohort of 328 individuals with histological NAFLD, 23 patients with ferritin >750 ng/ml and positive iron staining, and 25 controls with normal ferritin and negative iron staining, were selected. Patients with increased transferrin saturation, anemia, inflammation, β-thalassemia trait, HFE genotype at risk of iron overload and ferroportin mutations were excluded. A panel of 32 iron genes was re-sequenced. Literature and in silico predictions were employed for prioritization of pathogenic mutations. RESULTS Patients with hyperferritinemia had a higher prevalence of potentially pathogenic rare variants (73.9% vs. 20%, p = 0.0002) associated with higher iron stores and more severe liver fibrosis (p <0.05). Ceruloplasmin was the most mutated gene and its variants were independently associated with hyperferritinemia, hepatic siderosis, and more severe liver fibrosis (p <0.05). In the overall cohort, ceruloplasmin variants were independently associated with hyperferritinemia (adjusted odds ratio 5.99; 95% CI 1.83-19.60; p = 0.0009). CONCLUSIONS Variants in non-HFE iron genes, particularly ceruloplasmin, are associated with hyperferritinemia and increased hepatic iron stores in patients with NAFLD. Carriers of such variants have more severe liver fibrosis, suggesting that genetic predisposition to hepatic iron deposition may translate into liver disease. LAY SUMMARY Non-alcoholic fatty liver disease (NAFLD) is a common disease which can progress to cirrhosis and liver cancer. Increased levels of serum ferritin are often detected in patients with NAFLD and have been associated with altered iron metabolism and worse patient outcomes. We found that variants of genes related to iron metabolism, particularly ceruloplasmin, are associated with high ferritin levels, hepatic iron deposition and more severe liver disease in an Italian cohort of patients with NAFLD.
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Daniłowicz-Szymanowicz L, Świątczak M, Sikorska K, Starzyński RR, Raczak A, Lipiński P. Pathogenesis, Diagnosis, and Clinical Implications of Hereditary Hemochromatosis-The Cardiological Point of View. Diagnostics (Basel) 2021; 11:diagnostics11071279. [PMID: 34359361 PMCID: PMC8304945 DOI: 10.3390/diagnostics11071279] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 07/06/2021] [Accepted: 07/12/2021] [Indexed: 01/25/2023] Open
Abstract
Hereditary hemochromatosis (HH) is a genetic disease leading to excessive iron absorption, its accumulation, and oxidative stress induction causing different organ damage, including the heart. The process of cardiac involvement is slow and lasts for years. Cardiac pathology manifests as an impaired diastolic function and cardiac hypertrophy at first and as dilatative cardiomyopathy and heart failure with time. From the moment of heart failure appearance, the prognosis is poor. Therefore, it is crucial to prevent those lesions by upfront therapy at the preclinical phase of the disease. The most useful diagnostic tool for detecting cardiac involvement is echocardiography. However, during an early phase of the disease, when patients do not present severe abnormalities in serum iron parameters and severe symptoms of other organ involvement, heart damage may be overlooked due to the lack of evident signs of cardiac dysfunction. Considerable advancement in echocardiography, with particular attention to speckle tracking echocardiography, allows detecting discrete myocardial abnormalities and planning strategy for further clinical management before the occurrence of substantial heart damage. The review aims to present the current state of knowledge concerning cardiac involvement in HH. In addition, it could help cardiologists and other physicians in their everyday practice with HH patients.
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Affiliation(s)
- Ludmiła Daniłowicz-Szymanowicz
- Department of Cardiology and Electrotherapy, Medical University of Gdańsk, Dębinki 7 St., 80-211 Gdańsk, Poland;
- Correspondence: ; Tel.: +48-349-39-10
| | - Michał Świątczak
- Department of Cardiology and Electrotherapy, Medical University of Gdańsk, Dębinki 7 St., 80-211 Gdańsk, Poland;
| | - Katarzyna Sikorska
- Department of Tropical Medicine and Epidemiology, Medical University of Gdańsk, Dębinki 7 St., 80-211 Gdańsk, Poland;
| | - Rafał R. Starzyński
- Department of Molecular Biology, Institute of Genetics and Animal Breeding, Polish Academy of Sciences, Wólka Kosowska, 05-552 Jastrzębiec, Poland; (R.R.S.); (P.L.)
| | - Alicja Raczak
- Clinical Psychology Department, Faculty of Health Sciences, Medical University of Gdańsk, 80-211 Gdańsk, Poland;
| | - Paweł Lipiński
- Department of Molecular Biology, Institute of Genetics and Animal Breeding, Polish Academy of Sciences, Wólka Kosowska, 05-552 Jastrzębiec, Poland; (R.R.S.); (P.L.)
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Anderson GJ, Bardou-Jacquet E. Revisiting hemochromatosis: genetic vs. phenotypic manifestations. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:731. [PMID: 33987429 PMCID: PMC8106074 DOI: 10.21037/atm-20-5512] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Iron overload disorders represent an important class of human diseases. Of the primary iron overload conditions, by far the most common and best studied is HFE-related hemochromatosis, which results from homozygosity for a mutation leading to the C282Y substitution in the HFE protein. This disease is characterized by reduced expression of the iron-regulatory hormone hepcidin, leading to increased dietary iron absorption and iron deposition in multiple tissues including the liver, pancreas, joints, heart and pituitary. The phenotype of HFE-related hemochromatosis is quite variable, with some individuals showing little or no evidence of increased body iron, yet others showing severe iron loading, tissue damage and clinical sequelae. The majority of genetically predisposed individuals show at least some evidence of iron loading (increased transferrin saturation and serum ferritin), but a minority show clinical symptoms and severe consequences are rare. Thus, the disorder has a high biochemical penetrance, but a low clinical prevalence. Nevertheless, it is such a common condition in Caucasian populations (1:100–200) that it remains an important clinical entity. The phenotypic variability can largely be explained by a range of environmental, genetic and physiological factors. Men are far more likely to manifest significant disease than women, with the latter losing iron through menstrual blood loss and childbirth. Other forms of blood loss, immune system influences, the amount of bioavailable iron in the diet and lifestyle factors such as high alcohol intake can also contribute to iron loading and disease expression. Polymorphisms in a range of genes have been linked to variations in body iron levels, both in the general population and in hemochromatosis. Some of the genes identified play well known roles in iron homeostasis, yet others are novel. Other factors, including both co-morbidities and genetic polymorphisms, do not affect iron levels per se, but determine the propensity for tissue pathology.
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Affiliation(s)
- Gregory J Anderson
- Iron Metabolism Laboratory, QIMR Berghofer Medical Research Institute and School of Chemistry and Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia
| | - Edouard Bardou-Jacquet
- Liver Disease Department, University of Rennes and French Reference Center for Hemochromatosis and Iron Metabolism Disease, Rennes, France
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6
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Pelucchi S, Ravasi G, Arosio C, Mauri M, Piazza R, Mariani R, Piperno A. HIF1A: A Putative Modifier of Hemochromatosis. Int J Mol Sci 2021; 22:ijms22031245. [PMID: 33513852 PMCID: PMC7865586 DOI: 10.3390/ijms22031245] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/22/2021] [Accepted: 01/22/2021] [Indexed: 12/20/2022] Open
Abstract
HFE-related hereditary hemochromatosis (HH) is characterized by marked phenotypic heterogeneity. Homozygosity for p.C282Y is a low penetrance genotype suggesting that the HFE-HH is a multifactorial disease resulting from a complex interaction involving a major gene defect, genetic background and environmental factors. We performed a targeted NGS-based gene panel to identify new candidate modifiers by using an extreme phenotype sampling study based on serum ferritin and iron removed/age ratio. We found an increased prevalence of the HIF1A p.Phe582Ser and p.Ala588Thr variants in patients with a severe iron and clinical phenotype. Accordingly, Huh-7 cells transfected with both variants showed significantly lower HAMP promoter activity by luciferase assay. The qRT-PCR assays showed a downregulation of hepcidin and an upregulation of the HIF1A target genes (VEGF, HMOX, FUR, TMPRSS6) in cells transfected with the HIF1A-P582S vector. We identified mutations in other genes (e.g., Serpina1) that might have some relevance in single cases in aggravating or mitigating disease manifestation. In conclusion, the present study identified HIF1A as a possible modifier of the HFE-HH phenotype cooperating with the genetic defect in downregulating hepcidin synthesis. In addition, this study highlights that an NGS-based approach could broaden our knowledge and help in characterizing the genetic complexity of HFE-HH patients with a severe phenotype expression.
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Affiliation(s)
- Sara Pelucchi
- Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (S.P.); (G.R.); (M.M.); (R.P.)
| | - Giulia Ravasi
- Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (S.P.); (G.R.); (M.M.); (R.P.)
| | - Cristina Arosio
- Liceo Artistico Statale Amedeo Modigliani, 20833 Giussano, Italy;
| | - Mario Mauri
- Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (S.P.); (G.R.); (M.M.); (R.P.)
| | - Rocco Piazza
- Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (S.P.); (G.R.); (M.M.); (R.P.)
- Hematology and Clinical Research Unit, ASST-Monza, San Gerardo Hospital Monza, 20900 Monza, Italy
| | - Raffaella Mariani
- Centre of European Reference Network (EuroBloodNet) and Centre for Rare Diseases-Disorders of Iron Metabolism-ASST-Monza, San Gerardo Hospital Monza, 20900 Monza, Italy;
| | - Alberto Piperno
- Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (S.P.); (G.R.); (M.M.); (R.P.)
- Centre of European Reference Network (EuroBloodNet) and Centre for Rare Diseases-Disorders of Iron Metabolism-ASST-Monza, San Gerardo Hospital Monza, 20900 Monza, Italy;
- Medical Genetics-ASST-Monza, S. Gerardo Hospital Monza, 20900 Monza, Italy
- Correspondence: ; Tel.: +39-039-233-3461
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7
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Dysregulated hepcidin response to dietary iron in male mice with reduced Gnpat expression. Biosci Rep 2020; 40:226001. [PMID: 32766721 PMCID: PMC7441371 DOI: 10.1042/bsr20201508] [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: 05/17/2020] [Revised: 07/13/2020] [Accepted: 08/06/2020] [Indexed: 11/17/2022] Open
Abstract
Exome sequencing has identified the glyceronephosphate O-acyltransferase (GNPAT) gene as a genetic modifier of iron overload in hereditary hemochromatosis (HH). Subjects with HFE (Homeostatic Iron Regulator) p.C282Y mutations and the GNPAT p.D519G variant had more iron loading compared with subjects without the GNPAT variant. In response to an oral iron challenge, women with GNPAT polymorphisms loaded more iron as compared with women without polymorphisms, reinforcing a role for GNPAT in iron homeostasis. The aim of the present study was to develop and characterize an animal model of disease to further our understanding of genetic modifiers, and in particular the role of GNPAT in iron homeostasis. We generated an Hfe/Gnpat mouse model reminiscent of the patients previously studied and studied these mice for up to 26 weeks. We also examined the effect of dietary iron loading on mice with reduced Gnpat expression. Gnpat heterozygosity in Hfe knockout mice does not play a role in systemic iron homeostasis; Gnpat+/− mice fed a high-iron diet, however, had lower hepatic hepcidin (HAMP) mRNA expression, whereas they have significantly higher serum iron levels and transferrin saturation compared with wildtype (WT) littermates on a similar diet. These results reinforce an independent role of GNPAT in systemic iron homeostasis, reproducing in an animal model, the observations in women with GNPAT polymorphisms subjected to an iron tolerance test.
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8
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Secondes ES, Wallace DF, Rishi G, McLaren GD, McLaren CE, Chen WP, Ramm LE, Powell LW, Ramm GA, Barton JC, Subramaniam VN. Increased frequency of GNPAT p.D519G in compound HFE p.C282Y/p.H63D heterozygotes with elevated serum ferritin levels. Blood Cells Mol Dis 2020; 85:102463. [PMID: 32652459 DOI: 10.1016/j.bcmd.2020.102463] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 06/30/2020] [Accepted: 06/30/2020] [Indexed: 12/12/2022]
Abstract
Glyceronephosphate O-acyltransferase (GNPAT) p.D519G (rs11558492) was identified as a genetic modifier correlated with more severe iron overload in hemochromatosis through whole-exome sequencing of HFE p.C282Y homozygotes with extreme iron phenotypes. We studied the prevalence of p.D519G in HFE p.C282Y/p.H63D compound heterozygotes, a genotype associated with iron overload in some patients. Cases were Australian participants with elevated serum ferritin (SF) levels ≥300μg/L (males) and ≥200μg/L (females); subjects whose SF levels were below these cut-offs were designated as controls. Samples were genotyped for GNPAT p.D519G. We compared the allele frequency of the present subjects, with/without elevated SF, to p.D519G frequency in public datasets. GNPAT p.D519G was more prevalent in our cohort of p.C282Y/p.H63D compound heterozygotes with elevated SF (37%) than European public datasets: 1000G 21%, gnomAD 20% and ESP 21%. We conclude that GNPAT p.D519G is associated with elevated SF in Australian HFE p.C282Y/p.H63D compound heterozygotes.
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Affiliation(s)
- Eriza S Secondes
- School of Biomedical Sciences, Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Queensland, Australia.
| | - Daniel F Wallace
- School of Biomedical Sciences, Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Queensland, Australia.
| | - Gautam Rishi
- School of Biomedical Sciences, Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Queensland, Australia.
| | - Gordon D McLaren
- Division of Hematology/Oncology, Department of Medicine, University of California, Irvine, CA, USA; Department of Veterans Affairs Long Beach Healthcare System, Long Beach, CA, USA.
| | | | - Wen-Pin Chen
- Chao Family Comprehensive Cancer Center, University of California, Irvine, CA.
| | - Louise E Ramm
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.
| | - Lawrie W Powell
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.
| | - Grant A Ramm
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.
| | - James C Barton
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA, Southern Iron Disorders Center, Birmingham, AL, USA
| | - V Nathan Subramaniam
- School of Biomedical Sciences, Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Queensland, Australia; QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.
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9
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Piperno A, Pelucchi S, Mariani R. Inherited iron overload disorders. Transl Gastroenterol Hepatol 2020; 5:25. [PMID: 32258529 DOI: 10.21037/tgh.2019.11.15] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 11/12/2019] [Indexed: 12/21/2022] Open
Abstract
Hereditary iron overload includes several disorders characterized by iron accumulation in tissues, organs, or even single cells or subcellular compartments. They are determined by mutations in genes directly involved in hepcidin regulation, cellular iron uptake, management and export, iron transport and storage. Systemic forms are characterized by increased serum ferritin with or without high transferrin saturation, and with or without functional iron deficient anemia. Hemochromatosis includes five different genetic forms all characterized by high transferrin saturation and serum ferritin, but with different penetrance and expression. Mutations in HFE, HFE2, HAMP and TFR2 lead to inadequate or severely reduced hepcidin synthesis that, in turn, induces increased intestinal iron absorption and macrophage iron release leading to tissue iron overload. The severity of hepcidin down-regulation defines the severity of iron overload and clinical complications. Hemochromatosis type 4 is caused by dominant gain-of-function mutations of ferroportin preventing hepcidin-ferroportin binding and leading to hepcidin resistance. Ferroportin disease is due to loss-of-function mutation of SLC40A1 that impairs the iron export efficiency of ferroportin, causes iron retention in reticuloendothelial cell and hyperferritinemia with normal transferrin saturation. Aceruloplasminemia is caused by defective iron release from storage and lead to mild microcytic anemia, low serum iron, and iron retention in several organs including the brain, causing severe neurological manifestations. Atransferrinemia and DMT1 deficiency are characterized by iron deficient erythropoiesis, severe microcytic anemia with high transferrin saturation and parenchymal iron overload due to secondary hepcidin suppression. Diagnosis of the different forms of hereditary iron overload disorders involves a sequential strategy that combines clinical, imaging, biochemical, and genetic data. Management of iron overload relies on two main therapies: blood removal and iron chelators. Specific therapeutic options are indicated in patients with atransferrinemia, DMT1 deficiency and aceruloplasminemia.
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Affiliation(s)
- Alberto Piperno
- Department of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.,Centre for Rare Diseases, Disorder of Iron Metabolism, ASST-Monza, S. Gerardo Hospital, Monza, Italy
| | - Sara Pelucchi
- Department of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Raffaella Mariani
- Centre for Rare Diseases, Disorder of Iron Metabolism, ASST-Monza, S. Gerardo Hospital, Monza, Italy
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10
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An P, Wang J, Wang H, Jiang L, Wang J, Min J, Wang F. Gnpat does not play an essential role in systemic iron homeostasis in murine model. J Cell Mol Med 2020; 24:4118-4126. [PMID: 32108988 PMCID: PMC7171407 DOI: 10.1111/jcmm.15068] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 01/14/2020] [Accepted: 01/16/2020] [Indexed: 12/13/2022] Open
Abstract
The GNPAT variant rs11558492 (p.D519G) was identified as a novel genetic factor that modifies the iron‐overload phenotype in homozygous carriers of the HFE p.C282Y variant. However, the reported effects of the GNPAT p.D519G variant vary among study populations. Here, we investigated the role of GNPAT in iron metabolism using Gnpat‐knockout (Gnpat−/−), Gnpat/Hfe double‐knockout (Gnpat−/−Hfe−/− or DKO) mice and hepatocyte‐specific Gnpat‐knockout mice (Gnpatfl/fl;Alb‐Cre). Our analysis revealed no significant difference between wild‐type (Gnpat+/+) and Gnpat−/− mice, between Hfe−/− and DKO mice, or between Gnpatfl/fl and Gnpatfl/fl;Alb‐Cre with respect to serum iron and tissue iron. In addition, the expression of hepcidin was not affected by deleting Gnpat expression in the presence or absence of Hfe. Feeding Gnpat−/− and DKO mice a high‐iron diet had no effect on tissue iron levels compared with wild‐type and Hfe−/− mice, respectively. Gnpat knockdown in primary hepatocytes from wild‐type or Hfe−/− mice did not alter hepcidin expression, but it repressed BMP6‐induced hepcidin expression. Taken together, these results support the hypothesis that deleting Gnpat expression has no effect on either systemic iron metabolism or the iron‐overload phenotype that develops in Hfe−/− mice, suggesting that GNPAT does not directly mediate iron homeostasis under normal or high‐iron dietary conditions.
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Affiliation(s)
- Peng An
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing, China
| | - Jiaming Wang
- School of Public Health, The First Affiliated Hospital, Institute of Translational Medicine, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Medicine, Zhejiang University, Hangzhou, China
| | - Hao Wang
- Precision Nutrition Innovation Center, School of Public Health, Zhengzhou University, Zhengzhou, China
| | - Li Jiang
- School of Public Health, The First Affiliated Hospital, Institute of Translational Medicine, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Medicine, Zhejiang University, Hangzhou, China
| | - Jia Wang
- Precision Nutrition Innovation Center, School of Public Health, Zhengzhou University, Zhengzhou, China
| | - Junxia Min
- School of Public Health, The First Affiliated Hospital, Institute of Translational Medicine, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Medicine, Zhejiang University, Hangzhou, China
| | - Fudi Wang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing, China.,School of Public Health, The First Affiliated Hospital, Institute of Translational Medicine, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Medicine, Zhejiang University, Hangzhou, China.,Precision Nutrition Innovation Center, School of Public Health, Zhengzhou University, Zhengzhou, China
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11
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Stölzel U, Doss MO, Schuppan D. Clinical Guide and Update on Porphyrias. Gastroenterology 2019; 157:365-381.e4. [PMID: 31085196 DOI: 10.1053/j.gastro.2019.04.050] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 04/07/2019] [Accepted: 04/10/2019] [Indexed: 12/24/2022]
Abstract
Physicians should be aware of porphyrias, which could be responsible for unexplained gastrointestinal, neurologic, or skin disorders. Despite their relative rarity and complexity, most porphyrias can be easily defined and diagnosed. They are caused by well-characterized enzyme defects in the complex heme biosynthetic pathway and are divided into categories of acute vs non-acute or hepatic vs erythropoietic porphyrias. Acute hepatic porphyrias (acute intermittent porphyria, variegate porphyria, hereditary coproporphyria, and aminolevulinic acid dehydratase deficient porphyria) manifest in attacks and are characterized by overproduction of porphyrin precursors, producing often serious abdominal, psychiatric, neurologic, or cardiovascular symptoms. Patients with variegate porphyria and hereditary coproporphyria can present with skin photosensitivity. Diagnosis relies on measurement of increased urinary 5-aminolevulinic acid (in patients with aminolevulinic acid dehydratase deficient porphyria) or increased 5-aminolevulinic acid and porphobilinogen (in patients with other acute porphyrias). Management of attacks requires intensive care, strict avoidance of porphyrinogenic drugs and other precipitating factors, caloric support, and often heme therapy. The non-acute porphyrias are porphyria cutanea tarda, erythropoietic protoporphyria, X-linked protoporphyria, and the rare congenital erythropoietic porphyria. They lead to the accumulation of porphyrins that cause skin photosensitivity and occasionally severe liver damage. Secondary elevated urinary or blood porphyrins can occur in patients without porphyria, for example, in liver diseases, or iron deficiency. Increases in porphyrin precursors and porphyrins are also found in patients with lead intoxication. Patients with porphyria cutanea tarda benefit from iron depletion, hydroxychloroquine therapy, and, if applicable, elimination of the hepatitis C virus. An α-melanocyte-stimulating hormone analogue can reduce sunlight sensitivity in patients with erythropoietic protoporphyria or X-linked protoporphyria. Strategies to address dysregulated or dysfunctional steps within the heme biosynthetic pathway are in development.
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Affiliation(s)
- Ulrich Stölzel
- Saxony Porphyria Center, Department of Internal Medicine II, Klinikum Chemnitz, Chemnitz, Germany
| | - Manfred O Doss
- German Competence Center for Porphyria Diagnosis and Consultation, Marburg, Germany; Institute of Translational Immunology and Research Center for Immune Therapy, University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Detlef Schuppan
- Institute of Translational Immunology and Research Center for Immune Therapy, University Medical Center, Johannes Gutenberg University, Mainz, Germany; Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
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Abstract
Haemochromatosis is defined as systemic iron overload of genetic origin, caused by a reduction in the concentration of the iron regulatory hormone hepcidin, or a reduction in hepcidin-ferroportin binding. Hepcidin regulates the activity of ferroportin, which is the only identified cellular iron exporter. The most common form of haemochromatosis is due to homozygous mutations (specifically, the C282Y mutation) in HFE, which encodes hereditary haemochromatosis protein. Non-HFE forms of haemochromatosis due to mutations in HAMP, HJV or TFR2 are much rarer. Mutations in SLC40A1 (also known as FPN1; encoding ferroportin) that prevent hepcidin-ferroportin binding also cause haemochromatosis. Cellular iron excess in HFE and non-HFE forms of haemochromatosis is caused by increased concentrations of plasma iron, which can lead to the accumulation of iron in parenchymal cells, particularly hepatocytes, pancreatic cells and cardiomyocytes. Diagnosis is noninvasive and includes clinical examination, assessment of plasma iron parameters, imaging and genetic testing. The mainstay therapy is phlebotomy, although iron chelation can be used in some patients. Hepcidin supplementation might be an innovative future approach.
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Affiliation(s)
- Pierre Brissot
- INSERM, Univ. Rennes, INRA, Institut NUMECAN (Nutrition Metabolisms and Cancer) UMR_A 1341, UMR_S 1241, F-35000 Rennes, France
| | - Antonello Pietrangelo
- Division of Internal Medicine 2 and Center for Haemochromatosis, University Hospital of Modena, Modena, Italy
| | - Paul C. Adams
- Department of Medicine, University of Western Ontario, London, Ontario, Canada
| | - Barbara de Graaff
- Menzies Institute for Medical Research, University of Tasmania, Tasmania, Australia
| | | | - Olivier Loréal
- INSERM, Univ. Rennes, INRA, Institut NUMECAN (Nutrition Metabolisms and Cancer) UMR_A 1341, UMR_S 1241, F-35000 Rennes, France
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