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Lenglet H, Schmitt C, Grange T, Manceau H, Karboul N, Bouchet-Crivat F, Robreau AM, Nicolas G, Lamoril J, Simonin S, Mirmiran A, Karim Z, Casalino E, Deybach JC, Puy H, Peoc'h K, Gouya L. From a dominant to an oligogenic model of inheritance with environmental modifiers in acute intermittent porphyria. Hum Mol Genet 2019; 27:1164-1173. [PMID: 29360981 DOI: 10.1093/hmg/ddy030] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 01/09/2018] [Indexed: 01/02/2023] Open
Abstract
Acute intermittent porphyria (AIP) is a disease affecting the heme biosynthesis pathway caused by mutations of the hydroxymethylbilane synthase (HMBS) gene. AIP is thought to display autosomal dominant inheritance with incomplete penetrance. We evaluated the prevalence, penetrance and heritability of AIP, in families with the disease from the French reference center for porphyria (CFP) (602 overt patients; 1968 relatives) and the general population, using Exome Variant Server (EVS; 12 990 alleles) data. The pathogenicity of the 42 missense variants identified was assessed in silico, and in vitro, by measuring residual HMBS activity of the recombinant protein. The minimal estimated prevalence of AIP in the general population was 1/1299. Thus, 50 000 subjects would be expected to carry the AIP genetic trait in France. Penetrance was estimated at 22.9% in families with AIP, but at only 0.5-1% in the general population. Intrafamily correlation studies showed correlations to be strong overall and modulated by kinship and the area in which the person was living, demonstrating strong influences of genetic and environmental modifiers on inheritance. Null alleles were associated with a more severe phenotype and a higher penetrance than for other mutant alleles. In conclusion, the striking difference in the penetrance of HMBS mutations between the general population and the French AIP families suggests that AIP inheritance does not follow the classical autosomal dominant model, instead of being modulated by strong environmental and genetic factors independent from HMBS. An oligogenic inheritance model with environmental modifiers might better explain AIP penetrance and heritability.
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Affiliation(s)
- Hugo Lenglet
- UMRs 1149, Centre de Recherche sur l'Inflammation, Institut National de la Santé et de la Recherche Médicale, F-75018 Paris, France.,Département des Urgences, Assistance Publique-Hôpitaux de Paris, HUPNVS, Hôpital Bichat, F-75018 Paris, France
| | - Caroline Schmitt
- UMRs 1149, Centre de Recherche sur l'Inflammation, Institut National de la Santé et de la Recherche Médicale, F-75018 Paris, France.,Université Paris Diderot, F-75018 Paris, France.,Centre Français des Porphyries, Assistance Publique-Hôpitaux de Paris, HUPNVS, Hôpital Louis Mourier, F-92701 Colombes, France
| | - Thomas Grange
- INSERM UMR_S1048 Laboratory for Vascular Translational Science (LVTS) Université Paris Diderot, F-75018 Paris, France
| | - Hana Manceau
- UMRs 1149, Centre de Recherche sur l'Inflammation, Institut National de la Santé et de la Recherche Médicale, F-75018 Paris, France.,Laboratoire de Biochimie, Assistance Publique-Hôpitaux de Paris, HUPNVS, Hôpital Beaujon, 92110 Clichy, France and DHU Unity
| | - Narjesse Karboul
- UMRs 1149, Centre de Recherche sur l'Inflammation, Institut National de la Santé et de la Recherche Médicale, F-75018 Paris, France
| | - Florian Bouchet-Crivat
- UMRs 1149, Centre de Recherche sur l'Inflammation, Institut National de la Santé et de la Recherche Médicale, F-75018 Paris, France
| | - Anne-Marie Robreau
- UMRs 1149, Centre de Recherche sur l'Inflammation, Institut National de la Santé et de la Recherche Médicale, F-75018 Paris, France.,Centre Français des Porphyries, Assistance Publique-Hôpitaux de Paris, HUPNVS, Hôpital Louis Mourier, F-92701 Colombes, France
| | - Gael Nicolas
- UMRs 1149, Centre de Recherche sur l'Inflammation, Institut National de la Santé et de la Recherche Médicale, F-75018 Paris, France
| | - Jerôme Lamoril
- Département de Génétique, Assistance Publique-Hôpitaux de Paris, HUPNVS, Hôpital Bichat, F-75018 Paris, France
| | - Sylvie Simonin
- Centre Français des Porphyries, Assistance Publique-Hôpitaux de Paris, HUPNVS, Hôpital Louis Mourier, F-92701 Colombes, France
| | - Arienne Mirmiran
- UMRs 1149, Centre de Recherche sur l'Inflammation, Institut National de la Santé et de la Recherche Médicale, F-75018 Paris, France
| | - Zoubida Karim
- UMRs 1149, Centre de Recherche sur l'Inflammation, Institut National de la Santé et de la Recherche Médicale, F-75018 Paris, France
| | - Enrique Casalino
- Département des Urgences, Assistance Publique-Hôpitaux de Paris, HUPNVS, Hôpital Bichat, F-75018 Paris, France.,Université Paris Diderot, F-75018 Paris, France
| | - Jean-Charles Deybach
- UMRs 1149, Centre de Recherche sur l'Inflammation, Institut National de la Santé et de la Recherche Médicale, F-75018 Paris, France.,Université Paris Diderot, F-75018 Paris, France.,Centre Français des Porphyries, Assistance Publique-Hôpitaux de Paris, HUPNVS, Hôpital Louis Mourier, F-92701 Colombes, France
| | - Hervé Puy
- UMRs 1149, Centre de Recherche sur l'Inflammation, Institut National de la Santé et de la Recherche Médicale, F-75018 Paris, France.,Université Paris Diderot, F-75018 Paris, France.,Centre Français des Porphyries, Assistance Publique-Hôpitaux de Paris, HUPNVS, Hôpital Louis Mourier, F-92701 Colombes, France.,Laboratory of Excellence GR-Ex, F-75015 Paris, France
| | - Katell Peoc'h
- UMRs 1149, Centre de Recherche sur l'Inflammation, Institut National de la Santé et de la Recherche Médicale, F-75018 Paris, France.,Université Paris Diderot, F-75018 Paris, France.,Laboratoire de Biochimie, Assistance Publique-Hôpitaux de Paris, HUPNVS, Hôpital Beaujon, 92110 Clichy, France and DHU Unity.,Laboratory of Excellence GR-Ex, F-75015 Paris, France
| | - Laurent Gouya
- UMRs 1149, Centre de Recherche sur l'Inflammation, Institut National de la Santé et de la Recherche Médicale, F-75018 Paris, France.,Université Paris Diderot, F-75018 Paris, France.,Centre Français des Porphyries, Assistance Publique-Hôpitaux de Paris, HUPNVS, Hôpital Louis Mourier, F-92701 Colombes, France.,Laboratory of Excellence GR-Ex, F-75015 Paris, France
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Tchernitchko D, Tavernier Q, Lamoril J, Schmitt C, Talbi N, Lyoumi S, Robreau AM, Karim Z, Gouya L, Thervet E, Karras A, Puy H, Pallet N. A Variant of Peptide Transporter 2 Predicts the Severity of Porphyria-Associated Kidney Disease. J Am Soc Nephrol 2016; 28:1924-1932. [PMID: 28031405 DOI: 10.1681/asn.2016080918] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 11/29/2016] [Indexed: 01/15/2023] Open
Abstract
CKD occurs in most patients with acute intermittent porphyria (AIP). During AIP, δ-aminolevulinic acid (ALA) accumulates and promotes tubular cell death and tubulointerstitial damage. The human peptide transporter 2 (PEPT2) expressed by proximal tubular cells mediates the reabsorption of ALA, and variants of PEPT2 have different affinities for ALA. We tested the hypothesis that PEPT2 genotypes affect the severity and prognosis of porphyria-associated kidney disease. We analyzed data from 122 individuals with AIP who were followed from 2003 to 2013 and genotyped for PEPT2 At last follow-up, carriers of the PEPT2*1*1 genotype (higher affinity variant) exhibited worse renal function than carriers of the lower affinity variants PEPT2*1/*2 and PEPT2*2/*2 (mean±SD eGFR: 54.4±19.1, 66.6±23.8, and 78.1±19.9 ml/min per 1.73 m2, respectively). Change in eGFR (mean±SD) over the 10-year period was -11.0±3.3, -2.4±1.9, and 3.4±2.6 ml/min per 1.73 m2 for PEPT2*1/*1, PEPT2*1*2, and PEPT*2*2*2 carriers, respectively. At the end of follow-up, 68% of PEPT2*1*1 carriers had an eGFR<60 ml/min per 1.73 m2, compared with 37% of PEPT2*1*2 carriers and 15% of PEPT2*2*2 carriers. Multiple regression models including all confounders indicated that the PEPT2*1*1 genotype independently associated with an eGFR<60 ml/min per 1.73 m2 (odds ratio, 6.85; 95% confidence interval, 1.34 to 46.20) and an annual decrease in eGFR of >1 ml/min per 1.73 m2 (odds ratio, 3.64; 95% confidence interval, 1.37 to 9.91). Thus, a gene variant is predictive of the severity of a chronic complication of AIP. The therapeutic value of PEPT2 inhibitors in preventing porphyria-associated kidney disease warrants investigation.
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Affiliation(s)
- Dimitri Tchernitchko
- Centre Français des Porphyries, Hôpital Louis Mourier, Assistance Publique-Hôpitaux de Paris, Colombes, Paris, France.,Institut National pour la Santé et la Recherche Médicale (INSERM) U1149, Center for Research on Inflammation (CRI), Site Bichat, Paris, France
| | - Quentin Tavernier
- Institut National pour la Santé et la Recherche Médicale (INSERM) U1147, Centre Universitaire des Saints Pères, Paris, France.,Université Paris Descartes, Paris, France
| | - Jérôme Lamoril
- Centre Français des Porphyries, Hôpital Louis Mourier, Assistance Publique-Hôpitaux de Paris, Colombes, Paris, France.,Institut National pour la Santé et la Recherche Médicale (INSERM) U1149, Center for Research on Inflammation (CRI), Site Bichat, Paris, France
| | - Caroline Schmitt
- Centre Français des Porphyries, Hôpital Louis Mourier, Assistance Publique-Hôpitaux de Paris, Colombes, Paris, France.,Institut National pour la Santé et la Recherche Médicale (INSERM) U1149, Center for Research on Inflammation (CRI), Site Bichat, Paris, France.,Université Paris Diderot, Paris, France.,Laboratory of Excellence, GR-Ex, Paris, France
| | - Neila Talbi
- Centre Français des Porphyries, Hôpital Louis Mourier, Assistance Publique-Hôpitaux de Paris, Colombes, Paris, France
| | - Said Lyoumi
- Institut National pour la Santé et la Recherche Médicale (INSERM) U1149, Center for Research on Inflammation (CRI), Site Bichat, Paris, France.,Université Versailles Saint Quentin, Versailles, France; and
| | - Anne-Marie Robreau
- Centre Français des Porphyries, Hôpital Louis Mourier, Assistance Publique-Hôpitaux de Paris, Colombes, Paris, France.,Institut National pour la Santé et la Recherche Médicale (INSERM) U1149, Center for Research on Inflammation (CRI), Site Bichat, Paris, France
| | - Zoubida Karim
- Institut National pour la Santé et la Recherche Médicale (INSERM) U1149, Center for Research on Inflammation (CRI), Site Bichat, Paris, France
| | - Laurent Gouya
- Centre Français des Porphyries, Hôpital Louis Mourier, Assistance Publique-Hôpitaux de Paris, Colombes, Paris, France.,Institut National pour la Santé et la Recherche Médicale (INSERM) U1149, Center for Research on Inflammation (CRI), Site Bichat, Paris, France.,Université Paris Diderot, Paris, France.,Laboratory of Excellence, GR-Ex, Paris, France
| | - Eric Thervet
- Institut National pour la Santé et la Recherche Médicale (INSERM) U1147, Centre Universitaire des Saints Pères, Paris, France.,Université Paris Diderot, Paris, France.,Laboratory of Excellence, GR-Ex, Paris, France
| | - Alexandre Karras
- Institut National pour la Santé et la Recherche Médicale (INSERM) U1147, Centre Universitaire des Saints Pères, Paris, France.,Université Paris Diderot, Paris, France.,Laboratory of Excellence, GR-Ex, Paris, France
| | - Hervé Puy
- Centre Français des Porphyries, Hôpital Louis Mourier, Assistance Publique-Hôpitaux de Paris, Colombes, Paris, France.,Institut National pour la Santé et la Recherche Médicale (INSERM) U1149, Center for Research on Inflammation (CRI), Site Bichat, Paris, France.,Université Paris Diderot, Paris, France.,Laboratory of Excellence, GR-Ex, Paris, France
| | - Nicolas Pallet
- Institut National pour la Santé et la Recherche Médicale (INSERM) U1147, Centre Universitaire des Saints Pères, Paris, France; .,Université Paris Descartes, Paris, France.,Service de Néphrologie and.,Service de Biochimie, Hôpital Européen Georges Pompidou, Assistance Publique-Hôpitaux de Paris, Paris, France
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Daher R, Kannengiesser C, Houamel D, Lefebvre T, Bardou-Jacquet E, Ducrot N, de Kerguenec C, Jouanolle AM, Robreau AM, Oudin C, Le Gac G, Moulouel B, Loustaud-Ratti V, Bedossa P, Valla D, Gouya L, Beaumont C, Brissot P, Puy H, Karim Z, Tchernitchko D. Heterozygous Mutations in BMP6 Pro-peptide Lead to Inappropriate Hepcidin Synthesis and Moderate Iron Overload in Humans. Gastroenterology 2016; 150:672-683.e4. [PMID: 26582087 DOI: 10.1053/j.gastro.2015.10.049] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 10/14/2015] [Accepted: 10/29/2015] [Indexed: 02/08/2023]
Abstract
BACKGROUND & AIMS Hereditary hemochromatosis is a heterogeneous group of genetic disorders characterized by parenchymal iron overload. It is caused by defective expression of liver hepcidin, the main regulator of iron homeostasis. Iron stimulates the gene encoding hepcidin (HAMP) via the bone morphogenetic protein (BMP)6 signaling to SMAD. Although several genetic factors have been found to cause late-onset hemochromatosis, many patients have unexplained signs of iron overload. We investigated BMP6 function in these individuals. METHODS We sequenced the BMP6 gene in 70 consecutive patients with a moderate increase in serum ferritin and liver iron levels who did not carry genetic variants associated with hemochromatosis. We searched for BMP6 mutations in relatives of 5 probands and in 200 healthy individuals (controls), as well as in 2 other independent cohorts of hyperferritinemia patients. We measured serum levels of hepcidin by liquid chromatography-tandem mass spectrometry and analyzed BMP6 in liver biopsy specimens from patients by immunohistochemistry. The functions of mutant and normal BMP6 were assessed in transfected cells using immunofluorescence, real-time quantitative polymerase chain reaction, and immunoblot analyses. RESULTS We identified 3 heterozygous missense mutations in BMP6 (p.Pro95Ser, p.Leu96Pro, and p.Gln113Glu) in 6 unrelated patients with unexplained iron overload (9% of our cohort). These mutations were detected in less than 1% of controls. p.Leu96Pro also was found in 2 patients from the additional cohorts. Family studies indicated dominant transmission. Serum levels of hepcidin were inappropriately low in patients. A low level of BMP6, compared with controls, was found in a biopsy specimen from 1 patient. In cell lines, the mutated residues in the BMP6 propeptide resulted in defective secretion of BMP6; reduced signaling via SMAD1, SMAD5, and SMAD8; and loss of hepcidin production. CONCLUSIONS We identified 3 heterozygous missense mutations in BMP6 in patients with unexplained iron overload. These mutations lead to loss of signaling to SMAD proteins and reduced hepcidin production. These mutations might increase susceptibility to mild-to-moderate late-onset iron overload.
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Affiliation(s)
- Raed Daher
- INSERM UMR1149, Centre de Recherche sur l'Inflammation, Paris, France; Université Paris Diderot, Site Bichat, Sorbonne Paris Cité, Paris, France; Laboratory of Excellence, GR-Ex, Paris, France
| | - Caroline Kannengiesser
- INSERM UMR1149, Centre de Recherche sur l'Inflammation, Paris, France; Université Paris Diderot, Site Bichat, Sorbonne Paris Cité, Paris, France; Laboratory of Excellence, GR-Ex, Paris, France; AP-HP, Département de Génétique, Hôpital Bichat, Paris, France
| | - Dounia Houamel
- INSERM UMR1149, Centre de Recherche sur l'Inflammation, Paris, France; Université Paris Diderot, Site Bichat, Sorbonne Paris Cité, Paris, France; Laboratory of Excellence, GR-Ex, Paris, France
| | - Thibaud Lefebvre
- INSERM UMR1149, Centre de Recherche sur l'Inflammation, Paris, France; Université Paris Diderot, Site Bichat, Sorbonne Paris Cité, Paris, France; Laboratory of Excellence, GR-Ex, Paris, France; AP-HP, Centre Français des Porphyries, Hôpital Louis Mourier, Colombes, France
| | | | - Nicolas Ducrot
- INSERM UMR1149, Centre de Recherche sur l'Inflammation, Paris, France; Université Paris Diderot, Site Bichat, Sorbonne Paris Cité, Paris, France; Laboratory of Excellence, GR-Ex, Paris, France
| | | | - Anne-Marie Jouanolle
- Department of Liver Disease and Molecular Genetics, CHU Rennes, Rennes, France; CHU Rennes, French Reference Center for Rare Iron Overload Diseases of Genetic Origin
| | - Anne-Marie Robreau
- AP-HP, Centre Français des Porphyries, Hôpital Louis Mourier, Colombes, France
| | - Claire Oudin
- AP-HP, Centre Français des Porphyries, Hôpital Louis Mourier, Colombes, France
| | - Gerald Le Gac
- INSERM U1078, Université de Brest, CHRU de Brest, Laboratoire de Génétique Moléculaire et d'Histocompatibilité, Bretagne, Brest, France
| | - Boualem Moulouel
- INSERM UMR1149, Centre de Recherche sur l'Inflammation, Paris, France
| | | | - Pierre Bedossa
- INSERM UMR1149, Centre de Recherche sur l'Inflammation, Paris, France; AP-HP, Laboratoire d'Anatomo-Pathologie, Hôpital Beaujon, Clichy, France
| | - Dominique Valla
- AP-HP, Département d'Hépatologie, Hôpital Beaujon, Clichy, France
| | - Laurent Gouya
- INSERM UMR1149, Centre de Recherche sur l'Inflammation, Paris, France; Université Paris Diderot, Site Bichat, Sorbonne Paris Cité, Paris, France; Laboratory of Excellence, GR-Ex, Paris, France; AP-HP, Centre Français des Porphyries, Hôpital Louis Mourier, Colombes, France
| | - Carole Beaumont
- INSERM UMR1149, Centre de Recherche sur l'Inflammation, Paris, France; Université Paris Diderot, Site Bichat, Sorbonne Paris Cité, Paris, France; Laboratory of Excellence, GR-Ex, Paris, France
| | - Pierre Brissot
- Department of Liver Disease and Molecular Genetics, CHU Rennes, Rennes, France
| | - Hervé Puy
- INSERM UMR1149, Centre de Recherche sur l'Inflammation, Paris, France; Université Paris Diderot, Site Bichat, Sorbonne Paris Cité, Paris, France; Laboratory of Excellence, GR-Ex, Paris, France; AP-HP, Centre Français des Porphyries, Hôpital Louis Mourier, Colombes, France
| | - Zoubida Karim
- INSERM UMR1149, Centre de Recherche sur l'Inflammation, Paris, France; Université Paris Diderot, Site Bichat, Sorbonne Paris Cité, Paris, France; Laboratory of Excellence, GR-Ex, Paris, France.
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Delaby C, Oustric V, Schmitt C, Muzeau F, Robreau AM, Letteron P, Couchi E, Yu A, Lyoumi S, Deybach JC, Puy H, Karim Z, Beaumont C, Grandchamp B, Demant P, Gouya L. Epistasis in iron metabolism: complex interactions between Cp, Mon1a, and Slc40a1 loci and tissue iron in mice. Mamm Genome 2013; 24:427-38. [PMID: 24121729 DOI: 10.1007/s00335-013-9479-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 08/29/2013] [Indexed: 11/29/2022]
Abstract
Disorders of iron metabolism are among the most common acquired and constitutive diseases. Hemochromatosis has a solid genetic basis and in Northern European populations it is usually associated with homozygosity for the C282Y mutation in the HFE protein. However, the penetrance of this mutation is incomplete and the clinical presentation is highly variable. The rare and common variants identified so far as genetic modifiers of HFE-related hemochromatosis are unable to account for the phenotypic heterogeneity of this disorder. There are wide variations in the basal iron status of common inbred mouse strains, and this diversity may reflect the genetic background of the phenotypic diversity under pathological conditions. We therefore examined the genetic basis of iron homeostasis using quantitative trait loci mapping applied to the HcB-15 recombinant congenic strains for tissue and serum iron indices. Two highly significant QTL containing either the N374S Mon1a mutation or the Ferroportin locus were found to be major determinants in spleen and liver iron loading. Interestingly, when considering possible epistatic interactions, the effects of Mon1a on macrophage iron export are conditioned by the genotype at the Slc40a1 locus. Only mice that are C57BL/10ScSnA homozygous at both loci display a lower spleen iron burden. Furthermore, the liver-iron lowering effect of the N374S Mon1a mutation is observed only in mice that display a nonsense mutation in the Ceruloplasmin (Cp) gene. This study highlights the existence of genetic interactions between Cp, Mon1a, and the Slc40a1 locus in iron metabolism, suggesting that epistasis may be a crucial determinant of the variable biological and clinical presentations in iron disorders.
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Gouya L, Muzeau F, Robreau AM, Letteron P, Couchi E, Lyoumi S, Deybach JC, Puy H, Fleming R, Demant P, Beaumont C, Grandchamp B. Genetic study of variation in normal mouse iron homeostasis reveals ceruloplasmin as an HFE-hemochromatosis modifier gene. Gastroenterology 2007; 132:679-86. [PMID: 17258727 DOI: 10.1053/j.gastro.2006.11.024] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2006] [Accepted: 11/02/2006] [Indexed: 01/10/2023]
Abstract
BACKGROUND & AIMS Genetic hemochromatosis is one of the most common genetic disorders, with progressive tissue iron overload leading to severe clinical complications. In Northern European populations, genetic hemochromatosis is usually caused by homozygosity for the C282Y mutation in the HFE protein. However, penetrance of this mutation is incomplete, suggesting that other genetic and environmental factors contribute to its differential biologic or clinical expression. METHODS To identify genes modifying iron homeostasis, we screened the 27 recombinant congenic strains of the C3H/DiSnA-C57BL/10ScSnA/Dem series for tissue and serum iron indices and genotyped 18 microsatellite markers in (C3H/DiSnA x HcB-2) F2 hybrid mice. RESULTS We identified 1 locus encompassing the Ceruloplasmin (Cp) gene with a strong linkage with liver iron, serum iron, and transferrin levels but not with spleen iron. Sequencing of Cp showed an R435X nonsense mutation in exon 7 in C3H/DiSnA mice. To evaluate whether Cp might act as a modifier gene of genetic hemochromatosis, we intercrossed C3H Hfe(-/-) and C3HDiSnA Cp(R435X/R435X) mice. As expected, we found that double-mutant mice deposited more iron in the liver than mice defective for either one or both genes. In contrast, Hfe(-/-) x Cp(R435/R435X) or Cp(R435X/R435X) x Hfe(+/-) showed 30% decrease in liver iron when compared with single mutant mice. CONCLUSIONS This study highlights the existence of complex interactions between Cp and HFE and represents the first example of a modifier gene with a protective effect, in which heterozygosity reduces the iron load in the context of HFE deficiency.
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Affiliation(s)
- Laurent Gouya
- INSERM U773, Centre de Recherche Biomédicale Bichat Beaujon CRB3, Université Paris 7 Denis Diderot, site Bichat, Paris, France
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Gouya L, Martin-Schmitt C, Robreau AM, Austerlitz F, Da Silva V, Brun P, Simonin S, Lyoumi S, Grandchamp B, Beaumont C, Puy H, Deybach JC. Contribution of a common single-nucleotide polymorphism to the genetic predisposition for erythropoietic protoporphyria. Am J Hum Genet 2006; 78:2-14. [PMID: 16385445 PMCID: PMC1380220 DOI: 10.1086/498620] [Citation(s) in RCA: 137] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2005] [Accepted: 10/03/2005] [Indexed: 11/03/2022] Open
Abstract
Erythropoietic protoporphyria (EPP) is an inherited disorder of heme biosynthesis that results from a partial deficiency of ferrochelatase (FECH). Recently, we have shown that the inheritance of the common hypomorphic IVS3-48C allele trans to a deleterious mutation reduces FECH activity to below a critical threshold and accounts for the photosensitivity seen in patients. Rare cases of autosomal recessive inheritance have been reported. We studied a cohort of 173 white French EPP families and a group of 360 unrelated healthy subjects from four ethnic groups. The prevalences of the recessive and dominant autosomal forms of EPP are 4% (95% confidence interval 1-8) and 95% (95% confidence interval 91-99), respectively. In 97.9% of dominant cases, an IVS3-48C allele is co-inherited with the deleterious mutation. The frequency of the IVS3-48C allele differs widely in the Japanese (43%), southeast Asian (31%), white French (11%), North African (2.7%), and black West African (<1%) populations. These differences can be related to the prevalence of EPP in these populations and could account for the absence of EPP in black subjects. The phylogenic origin of the IVS3-48C haplotypes strongly suggests that the IVS3-48C allele arose from a single recent mutational event. Estimation of the age of the IVS3-48C allele from haplotype data in white and Asian populations yields an estimated age three to four times younger in the Japanese than in the white population, and this difference may be attributable either to differing demographic histories or to positive selection for the IVS3-48C allele in the Asian population. Finally, by calculating the KA/KS ratio in humans and chimpanzees, we show that the FECH protein sequence is subject to strong negative pressure. Overall, EPP looks like a Mendelian disorder, in which the prevalence of overt disease depends mainly on the frequency of a single common single-nucleotide polymorphism resulting from a unique mutational event that occurred 60,000 years ago.
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Affiliation(s)
- Laurent Gouya
- INSERM Unite 656, Faculte de Medecine Xavier Bichat, Universite Paris VII, Paris, France
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Gouya L, Puy H, Robreau AM, Lyoumi S, Lamoril J, Da Silva V, Grandchamp B, Deybach JC. Modulation of penetrance by the wild-type allele in dominantly inherited erythropoietic protoporphyria and acute hepatic porphyrias. Hum Genet 2003; 114:256-62. [PMID: 14669009 DOI: 10.1007/s00439-003-1059-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2003] [Accepted: 10/29/2003] [Indexed: 11/29/2022]
Abstract
We have recently demonstrated that in an autosomal dominant porphyria, erythropoietic protoporphyria (EPP), the coinheritance of a ferrochelatase (FECH) gene defect and of a wild-type low-expressed FECH allele is generally involved in the clinical expression of EPP. This mechanism may provide a model for phenotype modulation by minor variations in the expression of the wild-type allele in the other three autosomal dominant porphyrias that exhibit incomplete penetrance: acute intermittent porphyria (AIP), variegata porphyria (VP) and hereditary coproporphyria (HC), which are caused by partial deficiencies of hydroxy-methyl bilane synthase (HMBS), protoporphyrinogen oxidase (PPOX) and coproporphyrinogen oxidase (CPO), respectively. Given the dominant mode of inheritance of EPP, VP, AIP and HC, we first confirmed that the 200 overtly porphyric subjects (55 EPP, 58 AIP, 56 VP; 31 HC) presented a single mutation restricted to one allele (20 novel mutations and 162 known mutations). We then analysed the available single-nucleotide polymorphisms (SNPs) present at high frequencies in the general population and spreading throughout the FECH, HMBS, PPOX and the CPO genes in four case-control association studies. Finally, we explored the functional consequences of polymorphisms on the abundance of wild-type RNA, and used relative allelic mRNA determinations to find out whether low-expressed HMBS, PPOX and the CPO alleles occur in the general population. We confirm that the wild-type low-expressed allele phenomenon is usually operative in the mechanism of variable penetrance in EPP, but conclude that this is not the case in AIP and VP. For HC, the CPO mRNA determinations strongly suggest that normal CPO alleles with low-expression are present, but whether this low-expression of the wild-type allele could modulate the penetrance of a CPO gene defect in HC families remains to be ascertained.
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Affiliation(s)
- Laurent Gouya
- Centre Français des Porphyries, INSERM U 409, Faculté X Bichat, Hôpital Louis Mourier, 178 rue des Renouillers, 92701 Colombes Cedex, France
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Gouya L, Puy H, Robreau AM, Bourgeois M, Lamoril J, Da Silva V, Grandchamp B, Deybach JC. The penetrance of dominant erythropoietic protoporphyria is modulated by expression of wildtype FECH. Nat Genet 2002; 30:27-8. [PMID: 11753383 DOI: 10.1038/ng809] [Citation(s) in RCA: 195] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Erythropoietic protoporphyria (EPP) is an inherited disorder of heme biosynthesis caused by a partial deficiency of ferrochelatase (FECH, EC 4.99.1.1). EPP is transmitted as an autosomal dominant disorder with an incomplete penetrance. Using haplotype segregation analysis, we have identified an intronic single nucleotide polymorphism (SNP), IVS3-48T/C, that modulates the use of a constitutive aberrant acceptor splice site. The aberrantly spliced mRNA is degraded by a nonsense-mediated decay mechanism (NMD), producing a decreased steady-state level of mRNA and the additional FECH enzyme deficiency necessary for EPP phenotypic expression.
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Affiliation(s)
- Laurent Gouya
- Centre Francais des Porphyries, INSERM U 409, Faculté X. Bichat, Hôpital Louis Mourier, 92701 Colombes Cedex, France
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Gross U, Puy H, Doss M, Robreau AM, Nordmann Y, Doss MO, Deybach JC. New mutations of the hydroxymethylbilane synthase gene in German patients with acute intermittent porphyria. Mol Cell Probes 1999; 13:443-7. [PMID: 10657149 DOI: 10.1006/mcpr.1999.0276] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Acute intermittent porphyria (AIP) is a low-penetrant, autosomal dominant disorder caused by decreased activity of hydroxymethylbilane synthase (HMBS; MIM 176 000), the third enzyme in the heme biosynthetic pathway. We report the first molecular analysis of HMBS gene mutations in classical AIP patients of German origin. The HMBS gene of 5 German AIP patients was analysed by DGGE-screening and direct sequencing of amplified genomic DNA. Five different mutations including four novel mutations were found. Three of them are single base substitutions that affected exon 3 (R16C), exon 10 (V202L), and intron 13 (T to A, IVS13+2) The two remaining mutations are frameshifts which produce a stop codon (del GA in exon 6 and insA in exon 14). These mutations are likely to be responsible for the decrease in HMBS activity found in both erythrocytes and non-erythroid cell lines (lymphocytes). Our results demonstrate the allelic heterogeneity of HMBS mutations in AIP patients of German origin.
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Affiliation(s)
- U Gross
- Division of Clinical Biochemistry, Faculty of Medicine, Marburg, Federal Republic of Germany.
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Whatley SD, Puy H, Morgan RR, Robreau AM, Roberts AG, Nordmann Y, Elder GH, Deybach JC. Variegate porphyria in Western Europe: identification of PPOX gene mutations in 104 families, extent of allelic heterogeneity, and absence of correlation between phenotype and type of mutation. Am J Hum Genet 1999; 65:984-94. [PMID: 10486317 PMCID: PMC1288269 DOI: 10.1086/302586] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Variegate porphyria (VP) is a low-penetrance, autosomal dominant disorder characterized clinically by skin lesions and acute neurovisceral attacks that occur separately or together. It results from partial deficiency of protoporphyrinogen oxidase encoded by the PPOX gene. VP is relatively common in South Africa, where most patients have inherited the same mutation in the PPOX gene from a common ancestor, but few families from elsewhere have been studied. Here we describe the molecular basis and clinical features of 108 unrelated patients from France and the United Kingdom. Mutations in the PPOX gene were identified by a combination of screening (denaturing gradient gel electrophoresis, heteroduplex analysis, or denaturing high-performance liquid chromatography) and direct automated sequencing of amplified genomic DNA. A total of 60 novel and 6 previously reported mutations (25 missense, 24 frameshift, 10 splice site, and 7 nonsense) were identified in 104 (96%) of these unrelated patients, together with 3 previously unrecognized single-nucleotide polymorphisms. VP is less heterogeneous than other acute porphyrias; 5 mutations were present in 28 (26%) of the families, whereas 47 mutations were restricted to 1 family; only 2 mutations were found in both countries. The pattern of clinical presentation was identical to that reported from South Africa and was not influenced by type of mutation. Our results define the molecular genetics of VP in western Europe, demonstrate its allelic heterogeneity outside South Africa, and show that genotype is not a significant determinant of mode of presentation.
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Affiliation(s)
- S D Whatley
- Department of Medical Biochemistry, University of Wales College of Medicine, Heath Park, Cardiff, UK
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Tchernitchko D, Lamoril J, Puy H, Robreau AM, Bogard C, Rosipal R, Gouya L, Deybach JC, Nordmann Y. Evaluation of mutation screening by heteroduplex analysis in acute intermittent porphyria: comparison with denaturing gradient gel electrophoresis. Clin Chim Acta 1999; 279:133-43. [PMID: 10064125 DOI: 10.1016/s0009-8981(98)00056-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Acute intermittent porphyria is the major autosomal dominant form of acute hepatic porphyrias. The disease is due to mutations in the gene encoding for porphobilinogen deaminase (PBGD). Many different strategies have been developed to screen for mutations. However the high prevalence (0.6 per thousand) of PBGD gene defect, the large allelic heterogeneity of mutations (n = 130), and the limitations of the PBGD enzymatic assay for asymptomatic patients' detection, require for diagnosis an efficient and easy to handle strategy for locating mutations within the PBGD gene. In a recent study the sensitivity of the denaturing gradient gel electrophoresis (DGGE) technique was 100%. However DGGE requires the preparation of gradient gels and the use of primers with long GC-clamps; thus alternative methods should be preferable in the clinical laboratory. We have compared the detection rate of DGGE with heteroduplex analysis (HA) using 16 characterized PBGD gene mutations. Six different HA conditions were used to determine the efficiency of the method, including: (1) MDE (mutation detection enhancement) gel concentration; (2) addition of urea and sodium dodecyl sulfate (SDS); (3) radioactive labelling. The sensitivity of each HA condition varied from 31 to 81% vs. 100% in DGGE analysis. HA using 1 x MDE with 15% urea with or without 0.55% SDS was the most sensitive condition. This first comparative study of DGGE and HA mutation screening methods suggests that DGGE is a more sensitive screening assay than optimized HA. However, because of its simplicity HA should be considered as an efficient alternative mutation screening method.
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Affiliation(s)
- D Tchernitchko
- Centre Français des Porphyries, INSERM U409, Hôpital Louis Mourier, Colombes, France
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Nordmann Y, Puy H, Da Silva V, Simonin S, Robreau AM, Bonaiti C, Phung LN, Deybach JC. Acute intermittent porphyria: prevalence of mutations in the porphobilinogen deaminase gene in blood donors in France. J Intern Med 1997; 242:213-7. [PMID: 9350165 DOI: 10.1046/j.1365-2796.1997.00189.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVES Acute intermittent porphyria (AIP) is an autosomal dominant disorder resulting from a 50% deficiency in porphobilinogen deaminase (PBG deaminase). The true prevalence in the general population of mutations in the PBG deaminase gene capable of causing AIP is unknown. However, it is important to identify asymptomatic carriers of AIP mutations because all are at risk to have an acute attack. DESIGN We measured erythrocyte PBG deaminase from 3350 healthy blood donors. When a clear cut deficiency (< mean minus 2.5 SD) was found, the PBG deaminase gene was analysed by molecular biology technics. SUBJECTS Four subjects with PBG deaminase deficiency were identified. Two had mutations in the PBG deaminase gene which are known to cause AIP. CONCLUSION We conclude that, in France, the mutations of the PBG deaminase gene show a high prevalence in the healthy population. If only these two confirmed latent cases are used for the calculation, in France the minimal prevalence of the AIP gene is 1:1675.
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Affiliation(s)
- Y Nordmann
- Centre Français des Porphyries, Hopital Louis Mourier, Colombes, France
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Puy H, Deybach JC, Lamoril J, Robreau AM, Da Silva V, Gouya L, Grandchamp B, Nordmann Y. Molecular epidemiology and diagnosis of PBG deaminase gene defects in acute intermittent porphyria. Am J Hum Genet 1997; 60:1373-83. [PMID: 9199558 PMCID: PMC1716106 DOI: 10.1086/515455] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Acute intermittent porphyria (AIP) is the major autosomal dominant form of acute hepatic porphyrias. The disease is due to mutations in the gene encoding for porphobilinogen (PBG) deaminase and is characterized by life-threatening neurovisceral attacks, often precipitated by drugs, fasting, cyclical hormonal changes, or infectious diseases. This report describes a prospective study on the molecular epidemiology of PBG deaminase gene defects in AIP. It uses a sensitive, reliable, and easy-to-handle method for routine AIP molecular diagnosis and family study based on an exon-by-exon denaturing gradient gel electrophoresis (DGGE) strategy followed by direct sequencing. Fifteen genomic DNA fragments, including all the coding sequence and covering 3.35 kb of the PBG deaminase gene, were investigated in 405 subjects from 121 unrelated French Caucasian AIP families who had not been screened previously at the DNA level. PBG deaminase gene mutations were identified in 109 families, but only 78 were of different type, and each of them had a prevalence rate < 5%. Among these mutations, 33 had not been published previously. Sixty percent of these 78 mutations were located in only three exons (exons 10, 12, and 14), 44% were missense, 18% were splice defect, 19% were frameshift, and 16% were nonsense. In addition, two de novo mutational events were characterized. The evaluation of the efficiency of the standard PBG deaminase enzymatic screening method for gene-carrier detection indicated 95% of concordancy with the molecular-based diagnosis.
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Affiliation(s)
- H Puy
- Centre Français des Porphyries, INSERM U.409, Hôpital Louis Mourier, Colombes, France
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Puy H, Deybach JC, Lamoril J, Robreau AM, Nordmann Y. Detection of four novel mutations in the porphobilinogen deaminase gene in French Caucasian patients with acute intermittent porphyria. Hum Hered 1996; 46:177-80. [PMID: 8860014 DOI: 10.1159/000154349] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Acute intermittent porphyria (AIP) is an autosomal dominant disorder characterized by alterations of the gene encoding porphobilinogen deaminase (PBGD: EC 4.3.1.8), the third enzyme of the heme biosynthetic pathway. The molecular heterogeneity of the mutations causing AlP has been demonstrated with a reported predominance of single base substitutions resulting in amino acid changes. The molecular basis of AIP in four French patients was investigated using denaturing gradient gel electrophoresis followed by direct sequencing. We describe four different novel mutations that affected exon 12 (a frameshift and an exon skipping), exon 4 (a stop codon) and exon 15 (a frameshift inducing a stop codon). This study further documents the molecular heterogeneity of mutations in the PBGD gene in the French Caucasian population and reports types of mutations relatively uncommon in AIP.
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Affiliation(s)
- H Puy
- Centre Français des Porphyries (INSERM U-409), Hôpital Louis Mourier, Colombes, France
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