RESUMO
Ferritin is a hetero-oligomeric nanocage, composed of 24 subunits of two types, FTH1 and FTL. It protects the cell from excess reactive iron, by storing iron in its cavity. FTH1 is essential for the recruitment of iron into the ferritin nanocage and for cellular ferritin trafficking, whereas FTL contributes to nanocage stability and iron nucleation inside the cavity. Here we describe a female patient with a medical history of severe hypoferritinemia without anemia. Following inadequate heavy IV iron supplementation, the patient developed severe iron overload and musculoskeletal manifestations. However, her serum ferritin levels rose only to normal range. Genetic analyses revealed an undescribed homozygous variant of FTL (c.92A > G), which resulted in a Tyr31Cys substitution (FTLY31C ). Analysis of the FTL structure predicted that the Y31C mutation will reduce the variant's stability. Expression of the FTLY31C variant resulted in significantly lower cellular ferritin levels compared with the expression of wild-type FTL (FTLWT ). Proteasomal inhibition significantly increased the initial levels of FTLY31C , but could not protect FTLY31C subunits from successive degradation. Further, variant subunits successfully incorporated into hetero-polymeric nanocages in the presence of sufficient levels of FTH1. However, FTLY31C subunits poorly assembled into nanocages when FTH1 subunit levels were low. These results indicate an increased susceptibility of unassembled monomeric FTLY31C subunits to proteasomal degradation. The decreased cellular assembly of FTLY31C -rich nanocages may explain the low serum ferritin levels in this patient and emphasize the importance of a broader diagnostic approach of hypoferritinemia without anemia, before IV iron supplementation.
Assuntos
Anemia , Apoferritinas , Deficiências de Ferro , Sobrecarga de Ferro , Feminino , Humanos , Anemia/genética , Apoferritinas/genética , Apoferritinas/metabolismo , Ferritinas , Ferro/metabolismo , Deficiências de Ferro/genética , Sobrecarga de Ferro/genéticaRESUMO
BACKGROUND & AIMS: Ferroportin disease is a rare genetic iron overload disorder which may be underdiagnosed, with recent data suggesting it occurs at a higher prevalence than suspected. Costs and the lack of defined criteria to prompt genetic testing preclude large-scale molecular screening. Hence, we aimed to develop a readily available scoring system to promote and enhance ferroportin disease screening. METHODS: Our derivation cohort included probands tested for ferroportin disease from 2008 to 2016 in our rare disease network. Data were prospectively recorded. Univariate and multivariate logistic regression were used to determine significant criteria, and odds ratios were used to build a weighted score. A cut-off value was defined using a ROC curve with a predefined aim of 90% sensitivity. An independent cohort was used for cross validation. RESULTS: Our derivation cohort included 1,306 patients. Mean age was 55±14 years, ferritin 1,351±1,357 µg/L, and liver iron concentration (LIC) 166±77 µmol/g. Pathogenic variants (n = 32) were identified in 71 patients. In multivariate analysis: female sex, younger age, higher ferritin, higher LIC and the absence of hypertension or diabetes were significantly associated with the diagnosis of ferroportin disease (AUROC in whole derivation cohort 0.83 [0.78-0.88]). The weighted score was based on sex, age, the presence of hypertension or diabetes, ferritin level and LIC. An AUROC of 0.83 (0.77-0.88) was obtained in the derivation cohort without missing values. Using 9.5 as a cut-off, sensitivity was 93.6 (91.7-98.3) %, specificity 49.5 (45.5-53.6) %, positive likelihood ratio 1.8 (1.6-2.0) and negative likelihood ratio 0.17 (0.04-0.37). CONCLUSION: We describe a readily available score with simple criteria and good diagnostic performance that could be used to screen patients for ferroportin disease in routine clinical practice. LAY SUMMARY: Increased iron burden associated with metabolic syndrome is a very common condition. Ferroportin disease is a dominant genetic iron overload disorder whose prevalence is higher than initially thought. They can be difficult to distinguish from each other, but the limited availability of genetic testing and the lack of definitive guidelines prevent adequate screening. We herein describe a simple and definitive clinical score to help clinicians decide whether to perform genetic testing.
Assuntos
Proteínas de Transporte de Cátions/análise , Hemocromatose/diagnóstico , Projetos de Pesquisa/normas , Idoso , Proteínas de Transporte de Cátions/sangue , Estudos de Coortes , Feminino , Hemocromatose/sangue , Humanos , Ferro/metabolismo , Sobrecarga de Ferro/sangue , Sobrecarga de Ferro/complicações , Modelos Logísticos , Masculino , Programas de Rastreamento/métodos , Programas de Rastreamento/estatística & dados numéricos , Pessoa de Meia-Idade , Curva ROC , Projetos de Pesquisa/estatística & dados numéricosRESUMO
Congenital combined vitamin K-dependent clotting factors deficiency (VKCFD) is a rare autosomal recessive disease resulting in hemorrhagic symptoms usually associated with developmental disorders and bone abnormalities. Pathogenic variants in two genes encoding enzymes of the vitamin K cycle, GGCX and VKORC1, can lead to this disorder. We present the case of a male fetus with a brachytelephalangic chondrodysplasia punctata (CDP), absence of nasal bone, growth restriction, and bilateral ventriculomegaly at 18 weeks of gestation. Pathological examination showed a Binder phenotype, hypoplastic distal phalanges, stippled epiphyses, and brain abnormalities suggestive of a brain hemorrhage. Two GGCX pathogenic variants inherited respectively from the mother and the father were identified. To our knowledge, this is the first prenatal description of VKCFD. Even if it remains a rare etiology, which is mostly described in children or adult patients, VKCFD should be considered in fetuses with CDP.
Assuntos
Carbono-Carbono Ligases , Condrodisplasia Punctata , Fatores de Coagulação Sanguínea , Carbono-Carbono Ligases/genética , Condrodisplasia Punctata/diagnóstico , Condrodisplasia Punctata/genética , Feminino , Feto , Humanos , Masculino , Gravidez , Vitamina K , Vitamina K 1 , Vitamina K Epóxido Redutases/genéticaRESUMO
Severe iron overload is frequent in dehydrated hereditary stomatocytosis (DHSt) despite well-compensated hemolysis and no or little transfusion requirement. We investigated 4 patients with proven DHSt, in whom the degree of hemolysis was closely related to iron status. Genetic modifiers increasing iron stores (HFE:pCys282Tyr, HAMP:c-153C>T mutations) were accompanied with high liver iron concentrations and increased hemolysis, whereas therapeutic phlebotomies alleviated the hemolytic phenotype. There were no manifestations of hemolysis in one patient with low iron stores. Hemolysis reappeared when iron supplementation was given. The search for genetic or acquired modifiers of iron status and the modulation of iron stores may help in the management of these patients.
Assuntos
Anemia Hemolítica Congênita/diagnóstico , Anemia Hemolítica Congênita/metabolismo , Hidropisia Fetal/diagnóstico , Hidropisia Fetal/metabolismo , Ferro/metabolismo , Fenótipo , Adulto , Alelos , Anemia Hemolítica Congênita/sangue , Anemia Hemolítica Congênita/genética , Biomarcadores , Análise Mutacional de DNA , Feminino , Estudos de Associação Genética , Predisposição Genética para Doença , Genótipo , Proteína da Hemocromatose/genética , Humanos , Hidropisia Fetal/sangue , Hidropisia Fetal/genética , Masculino , Pessoa de Meia-Idade , Mutação , RadiografiaRESUMO
BACKGROUND & AIMS: Iron overload (IO) in HFE-related hereditary haemochromatosis is associated with increased risk of liver cancer. This study aimed to investigate the role of other genes involved in hereditary IO among patients with hepatocellular carcinoma (HCC). METHODS: Patients with HCC diagnosed in our institution were included in this prospective study. Those with ferritin levels ≥300 µg/L (males) or ≥200 µg/L (females) and/or transferrin saturation ≥50% (males) or ≥45% (females) had liver iron concentration (LIC) evaluated by MRI. HFE C282Y and H63D mutations were screened. Genetic analyses of genes involved in hereditary IO (HFE, HJV/HFE2, HAMP, TFR2, SLC40A1, GNPAT) were performed in patients with increased LIC. RESULTS: A total of 234 patients were included; 215 (92%) had common acquired risk factors of HCC (mainly alcoholism or chronic viral hepatitis). 119 patients had abnormal iron parameters. Twelve (5.1%) were C282Y homozygotes, three were compound C282Y/H63D heterozygotes. LIC was measured by MRI in 100 patients. Thirteen patients with a LIC>70 µmol/g were enrolled in further genetic analyses: two unrelated patients bore the HAMP:c.-153C>T mutation at the heterozygous state, which is associated with increased risk of IO and severe haemochromatosis. Specific haplotypes of SLC40A1 were also studied. CONCLUSIONS: Additional genetic risk factors of IO were found in 18 patients (7.7%) among a large series of 234 HCC patients. Screening for IO and the associated at-risk genotypes in patients who have developed HCC, is useful for both determining etiologic diagnosis and enabling family screening and possibly primary prevention in relatives.
Assuntos
Carcinoma Hepatocelular/complicações , Ferritinas/sangue , Sobrecarga de Ferro/genética , Neoplasias Hepáticas/complicações , Aciltransferases/genética , Idoso , Proteínas de Transporte de Cátions/genética , Feminino , França , Testes Genéticos , Genótipo , Proteína da Hemocromatose/genética , Hepcidinas/genética , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Mutação , Estudos Prospectivos , Análise de Sequência de DNARESUMO
BACKGROUND AND OBJECTIVE: A clinician was intrigued about HbA1c upper 9% (75 mmol/mol) in a 76 year-old women with normal glycemia. Further explorations were performed in order to understand this discordance. METHODS: First HbA1c test was performed on a HLC -723 G11 apparatus (Tosoh Bioscience) and thereafter compared to the HLC-723-G8 (Tosoh Bioscience), the Capillaris 3 Tera (Sebia) and the DCA Vantage point of care testing (POCT) (Siemens) apparatus. In addition, study of Hemoglobin (Hb) fraction and mutation analysis of HBB gene was realized due to the suspicion of an Hb variant. RESULTS: Twice high results of HbA1c (9.3%, 78 mmol/mol and 10%, 86 mmol/mol) on the HLC-723 G11 was not confirmed with other instruments. HbA1c result for the same sample was 5.2% (33 mmol/mol) for the HLC-723 G8, 5.3% (34 mmol/mol) for the Capillaris and 6.2% (44 mmol/mol) for the DCA Vantage POCT. The subject had normal glycemia and none signs of diabetes mellitus. An abnormal Hb fraction was visualized on the graphs for the HLC-723 G11 and Capillaris but not for the HLC-723 G8 analyzer. Study of Hb fraction confirmed the presence of an abnormal Hb fraction that was identifed as an Hb G-Copenhagen through mutation analysis of HBB gene. CONCLUSION: This case evidenced an interference on HbA1c test in presence of Hb G-Copenhagen depending to the analyzer used. This report help to alert of such possibility and to remain that a discordance between HbA1c and glycemia can be due to an Hb variant.
RESUMO
BACKGROUND: Heterozygotes for the p.Cys282Tyr (C282Y) mutation of the HFE gene do not usually express a hemochromatosis phenotype. Apart from the compound heterozygous state for C282Y and the widespread p.His63Asp (H63D) variant allele, other rare HFE mutations can be found in trans on chromosome 6. DESIGN AND METHODS: We performed molecular investigation of the genes implicated in hereditary hemochromatosis in six patients who presented with iron overload but were simple heterozygotes for the HFE C282Y mutation at first genetic testing. Functional impairment of new variants was deduced from computational methods including molecular modeling studies. RESULTS: We identified four rare HFE mutant alleles, three of which have not been previously described. One mutation is a 13-nucleotide deletion in exon 6 (c.1022_1034del13, p.His341_Ala345 > LeufsX119), which is predicted to lead to an elongated and unstable protein. The second one is a substitution of the last nucleotide of exon 2 (c.340G > A, p.Glu114Lys) which modifies the relative solvent accessibility in a loop interface. The third mutation, p.Arg67Cys, also lies in exon 2 and introduces a destabilization of the secondary structure within a loop of the α1 domain. We also found the previously reported c.548T > C (p.Leu183Pro) missense mutation in exon 3. No other known iron genes were mutated. We present an algorithm at the clinical and genetic levels for identifying patients deserving further investigation. Conclusions Our results suggest that additional mutations in HFE may have a clinical impact in C282Y carriers. In conjunction with results from previously described cases we conclude that an elevated transferrin saturation level and elevated hepatic iron index should indicate the utility of searching for further HFE mutations in C282Y heterozygotes prior to other iron gene studies.
Assuntos
Testes Genéticos , Variação Genética , Hemocromatose/complicações , Hemocromatose/genética , Antígenos de Histocompatibilidade Classe I/genética , Sobrecarga de Ferro/complicações , Sobrecarga de Ferro/genética , Proteínas de Membrana/genética , Adulto , Alelos , Feminino , Ferritinas/sangue , Ordem dos Genes , Hemocromatose/diagnóstico , Proteína da Hemocromatose , Heterozigoto , Humanos , Masculino , Pessoa de Meia-Idade , MutaçãoRESUMO
BACKGROUND: Despite great progress in understanding the mechanisms underlying genetic hemochromatosis, data on the prevalence and the penetrance of the disorder are conflicting. DESIGN AND METHODS: A registry of patients with genetic hemochromatosis was established in the South of France and a regional health network was developed to allow the inclusion of all the diagnosed patients. C282Y homozygous patients classified in stages 2 (biological iron overload), 3 and 4 (clinical manifestations of iron overload, stage 4 being the more severe) according to the classification of the French National Authority for Health were included in the registry over a 6-year period. RESULTS: A total of 352 symptomatic C282Y homozygotes were identified, resulting in a total prevalence of 1.83 per 10,000 (95% CI: 1.63 to 2.02) in subjects over 20 years and 2.40 per 10,000 (95% CI, 2.15 to 2.65) among subjects of European descent. Among Europeans, the total calculated penetrance was 15.8% in stage 2 or higher, 12.1% in stage 3 or 4 and 2.9% in stage 4. The penetrance was slightly higher in males (18.7%) than in females (13.2%). It was 19.9% for individuals over 40 years of age (24.1% and 16.3% in males and females, respectively) with a maximum of 31% in subjects between 50 and 54 years old. Among 249 patients with complete records, 24% were in stage 2, the majority (58%) were in stage 3, and 18% in stage 4. There was a higher proportion of males, and excessive alcohol intake was more prevalent in stage 4 than in stages 2 and 3 combined. CONCLUSIONS: A French Mediterranean regional hemochromatosis registry with strict inclusion criteria is a useful tool for characterizing the history of this disease, particularly for the most severely affected patients, as defined by the disease severity classification. The total prevalence of symptomatic C282Y homozygotes in the region was found to be low. However, clinical penetrance (stages 3 and 4) was not negligible.
Assuntos
Predisposição Genética para Doença , Hemocromatose/genética , Sobrecarga de Ferro/genética , Feminino , França/epidemiologia , Testes Genéticos , Genótipo , Hemocromatose/diagnóstico , Hemocromatose/epidemiologia , Homozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Mutação/genética , Penetrância , Sistema de Registros , População BrancaAssuntos
Regiões 5' não Traduzidas/genética , Apoferritinas/genética , Catarata/genética , Distúrbios do Metabolismo do Ferro/genética , Mutação , Sequência de Bases , Catarata/congênito , Análise Mutacional de DNA , Saúde da Família , Feminino , Homozigoto , Humanos , Distúrbios do Metabolismo do Ferro/congênito , Masculino , Pessoa de Meia-Idade , Linhagem , SíndromeAssuntos
Porfiria Cutânea Tardia/complicações , Esferocitose Hereditária/complicações , Feminino , Humanos , Pessoa de Meia-Idade , Porfiria Cutânea Tardia/diagnóstico , Porfiria Cutânea Tardia/terapia , Fatores de Risco , Pele/patologia , Esferocitose Hereditária/diagnóstico , Esferocitose Hereditária/genética , Esferocitose Hereditária/terapiaRESUMO
Hepcidin has progressively become essential in clinical practice for the diagnosis and follow-up of a large spectrum of diseases. Anyway, its own biochemical and structural characteristics have complicated and delayed the acquisition of a standardized quantifying tool of the peptide.
Assuntos
Hepcidinas/análise , Fatores Etários , Feminino , Regulação da Expressão Gênica , Hepcidinas/química , Hepcidinas/metabolismo , Hepcidinas/fisiologia , Humanos , Imunoensaio/métodos , Inflamação/genética , Inflamação/metabolismo , Inflamação/patologia , MasculinoRESUMO
During a screening program we identified a 5-year old girl with elevated iron parameters. The child was found to have a combination of a novel R176C mutation together with the G320V mutation in the juvenile hemochromatosis gene (HJV). The girl was also homozygous for the H63D mutation in HFE. The possibility of detecting juvenile hemochromatosis before the onset of clinical manifestations raises questions about the management of such young children in order to prevent iron overload.
Assuntos
Substituição de Aminoácidos , Hemocromatose/genética , Proteínas de Membrana/genética , Proteínas Mutantes/genética , Mutação de Sentido Incorreto , Mutação Puntual , Adulto , Pré-Escolar , Análise Mutacional de DNA , Diagnóstico Precoce , Éxons/genética , Feminino , Proteínas Ligadas por GPI , Testes Genéticos , Genótipo , Proteína da Hemocromatose , Antígenos de Histocompatibilidade Classe I/química , Antígenos de Histocompatibilidade Classe I/genética , Humanos , Ferro/sangue , Masculino , Proteínas de Membrana/química , Proteínas Mutantes/química , Polimorfismo de Fragmento de Restrição , Estrutura Terciária de Proteína , Transferrina/análiseRESUMO
Iron homeostasis is based on a strict control of both intestinal iron absorption and iron recycling through reticulo-endothelial system. Hepcidin controls the iron fluxes in order to maintain sufficient iron levels for erythropoietic activities, hemoproteins synthesis or enzymes function, but also to limit its toxic accumulation throughout the body. Hepcidin expression is regulated by various stimuli: inflammation and iron stimulate the production of the peptide, while anemia, erythropoiesis and hypoxia repress its production. Regulation of hepcidin expression is not so simple in complex pathological situations such as hemolytic anemia, cancer or chronic inflammation. Serum hepcidin quantification in association with the diagnostic tests currently available is quite promising for the diagnosis or the follow-up of anemia in those conditions. This study is part of the working group « Clinical interests of hepcidin quantification ¼ of the Société française de biologie clinique.
Assuntos
Anemia/complicações , Anemia/diagnóstico , Hepcidinas/análise , Hepcidinas/sangue , Monitorização Fisiológica/métodos , Biomarcadores/análise , Biomarcadores/sangue , Hepcidinas/fisiologia , Homeostase , Humanos , Inflamação/sangue , Inflamação/complicações , Ferro/sangue , Ferro/metabolismo , Valor Preditivo dos Testes , PrognósticoAssuntos
Proteínas de Transporte de Cátions/genética , Mutação , Porfiria Cutânea Tardia/genética , Adulto , Idoso , Transporte Biológico , Proteínas de Transporte de Cátions/metabolismo , Análise Mutacional de DNA , Feminino , França , Predisposição Genética para Doença , Proteína da Hemocromatose , Antígenos de Histocompatibilidade Classe I/genética , Humanos , Masculino , Proteínas de Membrana/genética , Pessoa de Meia-Idade , Fenótipo , Porfiria Cutânea Tardia/metabolismoAssuntos
Peptídeos Catiônicos Antimicrobianos/genética , Proteínas Ligadas por GPI/genética , Mutação , Porfiria Cutânea Tardia/genética , Adulto , Idoso , Feminino , Ferritinas/sangue , França , Frequência do Gene , Hemocromatose/genética , Proteína da Hemocromatose , Hepcidinas , Heterozigoto , Humanos , Sobrecarga de Ferro/genética , Masculino , Pessoa de Meia-Idade , Porfiria Cutânea Tardia/sangueRESUMO
INTRODUCTION: Radiotherapy (RT) is considered a standard treatment option after surgery for breast cancer. Letrozole, an aromatase inhibitor, is being evaluated in the adjuvant setting. We determined the effects of the combination of RT and letrozole in the aromatase-expressing breast tumour cell line MCF-7CA, stably transfected with the CYP19 gene. METHODS: Irradiations were performed using a cobalt-60 source with doses ranging from 0 to 4 Gy. Cells were incubated with androstenedione in the presence or absence of letrozole. Effects of treatment were evaluated using clonogenic assays, tetrazolium salt colorimetric (MTT) assays, and cell number determinations. Cell-cycle analyses were conducted using flow cytometry. RESULTS: The survival fraction at 2 Gy was 0.66 for RT alone and was 0.44 for RT plus letrozole (P = 0.02). Growth of MCF-7CA cells as measured by the cell number 6 days after radiotherapy (2 and 4 Gy) was decreased by 76% in those cells treated additionally with letrozole (0.7 microM) compared with those receiving radiotherapy alone (P = 0.009). Growth inhibition, assessed either by cell number (P = 0.009) or by the MTT assay (P = 0.02), was increased after 12 days of the combination treatment. Compared with radiation alone, the combination of radiation and letrozole produced a significant decrease in radiation-induced G2 phase arrest and a decrease of cells in the S phase, with cell redistribution in the G1 phase. CONCLUSIONS: These radiobiological results may form the basis for concurrent use of letrozole and radiation as postsurgical adjuvant therapy for breast cancer.
Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/patologia , Ciclo Celular/efeitos dos fármacos , Ciclo Celular/efeitos da radiação , Nitrilas/farmacologia , Radiossensibilizantes/farmacologia , Triazóis/farmacologia , Aromatase/biossíntese , Aromatase/genética , Sobrevivência Celular , Feminino , Citometria de Fluxo , Humanos , Letrozol , Radioterapia Adjuvante , TransfecçãoRESUMO
We describe a family with beta-thalassemia in which several pitfalls of genetic diagnoses were present. These include coherent family phenotypes with discrepancies in molecular findings because of nonpaternity, and a false beta-globin gene homozygous genotype due to a large deletion in the second locus. These findings underline the difficulties of family genetic studies and the need for tight relationship between professionals involved in laboratory studies and those in-charge of the clinical follow-up and genetic counselling. In this family, we also report a new silent beta-thalassemia mutation, -102 (C>A), in the distal CACCC box of the beta-globin gene promoter.