title: Molecular diagnosis of hypophosphatasia and differential diagnosis by targeted Next Generation Sequencing.
abstract: Hypophosphatasia (HPP) is a rare inherited skeletal dysplasia due to loss of function mutations in the ALPL gene. The disease is subject to an extremely high clinical heterogeneity ranging from a perinatal lethal form to odontohypophosphatasia affecting only teeth. Up to now genetic diagnosis of HPP is performed by sequencing the ALPL gene by Sanger methodology. Osteogenesis imperfecta (OI) and campomelic dysplasia (CD) are the main differential diagnoses of severe HPP, so that in case of negative result for ALPL mutations, OI and CD genes had often to be analyzed, lengthening the time before diagnosis. We report here our 18-month experience in testing 46 patients for HPP and differential diagnosis by targeted NGS and show that this strategy is efficient and useful. We used an array including ALPL gene, genes of differential diagnosis COL1A1 and COL1A2 that represent 90% of OI cases, SOX9, responsible for CD, and 8 potentially modifier genes of HPP. Seventeen patients were found to carry a mutation in one of these genes. Among them, only 10 out of 15 cases referred for HPP carried a mutation in ALPL and 5 carried a mutation in COL1A1 or COL1A2. Interestingly, three of these patients were adults with fractures and/or low BMD. Our results indicate that HPP and OI may be easily misdiagnosed in the prenatal stage but also in adults with mild symptoms for these diseases.
authors.affiliation: Unité de Génétique Constitutionnelle, Centre Hospitalier de Versailles, 78150 Le Chesnay, France. Electronic address: ataillandier@ch-versailles.fr.
authors.forename: Agnès
authors.initials: A
authors.lastname: Taillandier
authors.affiliation: Unité de Génétique Constitutionnelle, Centre Hospitalier de Versailles, 78150 Le Chesnay, France. Electronic address: christelle.adam1@voila.fr.
authors.forename: Christelle
authors.initials: C
authors.lastname: Domingues
authors.affiliation: Unité de Génétique Constitutionnelle, Centre Hospitalier de Versailles, 78150 Le Chesnay, France. Electronic address: c.de.casanove@outlook.fr.
authors.forename: Clémence
authors.initials: C
authors.lastname: De Cazanove
authors.affiliation: Endocrinologie, Maladies Osseuses, Génétique et Gynécologie Médicale, Hôpital des Enfants, CHU de Toulouse, Toulouse Cedex 9, France. Electronic address: porquet-bordes.v@chu-toulouse.fr.
authors.forename: Valérie
authors.initials: V
authors.lastname: Porquet-Bordes
authors.affiliation: Université Paris-Descartes, Sorbonne Paris Cité, Institut Imagine and INSERM U1163, Hôpital Necker-Enfants Malades, Paris, France. Electronic address: sophie.monnot@nck.aphp.fr.
authors.forename: Sophie
authors.initials: S
authors.lastname: Monnot
authors.affiliation: Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA. Electronic address: kiffer-moreira@sanfordburnham.org.
authors.forename: Tina
authors.initials: T
authors.lastname: Kiffer-Moreira
authors.affiliation: APHP, Bicêtre Paris Sud, Department of Pediatric Endocrinology and Diabetology for Children, Le Kremlin Bicêtre 94270, France; APHP, Reference Center for Rare Disorders of the Mineral Metabolism and Plateforme D'expertise Paris Sud, Le Kremlin Bicêtre 94270, France. Electronic address: anya.rothenbuhler@bct.aphp.fr.
authors.forename: Agnès
authors.initials: A
authors.lastname: Rothenbuhler
authors.affiliation: Service de Rhumatologie, Hôpital Sud, CHU de Rennes, 16, Boulevard de Bulgarie, BP90347, 35203 Rennes Cedex 2, France. Electronic address: pascal.guggenbuhl@chu-rennes.fr.
authors.forename: Pascal
authors.initials: P
authors.lastname: Guggenbuhl
authors.affiliation: Rheumatology Department, Cochin University Hospital, 75015 Paris, France. Electronic address: Catherine.Cormier@cch.ap-hop-paris.fr.
authors.forename: Catherine
authors.initials: C
authors.lastname: Cormier
authors.affiliation: Centres de Référence Maladies Osseuses Constitutionnelles (MOC), Hôpital Universitaire Necker-Enfants Malades et Institut Imagine (AP-HP), 75015 Paris, France. Electronic address: genevieve.baujat@nck.aphp.fr.
authors.forename: Geneviève
authors.initials: G
authors.lastname: Baujat
authors.affiliation: Service de rhumatologie, CHU de Poitiers, 86021 Poitiers Cedex, France. Electronic address: francoise.debiais@chu-poitiers.fr.
authors.forename: Françoise
authors.initials: F
authors.lastname: Debiais
authors.affiliation: Department of Genetics, APHP-Robert Debré University Hospital, Paris, France. Electronic address: yline.capri@aphp.fr.
authors.forename: Yline
authors.initials: Y
authors.lastname: Capri
authors.affiliation: Department of Rheumatology, INSERM UMR-1132, Lariboisière Hospital and University, Paris Diderot Sorbonne, Paris, France. Electronic address: martine.cohen-solal@inserm.fr.
authors.forename: Martine
authors.initials: M
authors.lastname: Cohen-Solal
authors.affiliation: Service de Génétique Clinique, CHU Brest, Brest F-29200, France. Electronic address: philippe.parent@chu-brest.fr.
authors.forename: Philippe
authors.initials: P
authors.lastname: Parent
authors.affiliation: Department of Genetics, University Hospital, Nîmes, France. Electronic address: jean.chiesa@chu-nimes.fr.
authors.forename: Jean
authors.initials: J
authors.lastname: Chiesa
authors.affiliation: Service de Génétique Clinique, CHU, Lille, France. Electronic address: anne.dieux@chru-lille.fr.
authors.forename: Anne
authors.initials: A
authors.lastname: Dieux
authors.affiliation: Service de Génétique Clinique, CHU, Lille, France. Electronic address: florence.petit@chru-lille.fr.
authors.forename: Florence
authors.initials: F
authors.lastname: Petit
authors.affiliation: Unité de Génétique Médicale, Centre Intercommunal Poissy-St-Germain en Laye, Poissy, France. Electronic address: drjroume@gmail.com.
authors.forename: Joelle
authors.initials: J
authors.lastname: Roume
authors.affiliation: Gynécologie Obstétrique, Centre Hospitalier de Mulhouse, 68051 Mulhouse Cedex, France.
authors.forename: Monica
authors.initials: M
authors.lastname: Isnard
authors.affiliation: Université Paris-Descartes, Sorbonne Paris Cité, Institut Imagine and INSERM U1163, Hôpital Necker-Enfants Malades, Paris, France. Electronic address: valerie.cormier-daire@inserm.fr.
authors.forename: Valérie
authors.initials: V
authors.lastname: Cormier-Daire
authors.affiliation: APHP, Bicêtre Paris Sud, Department of Pediatric Endocrinology and Diabetology for Children, Le Kremlin Bicêtre 94270, France; APHP, Reference Center for Rare Disorders of the Mineral Metabolism and Plateforme D'expertise Paris Sud, Le Kremlin Bicêtre 94270, France. Electronic address: agnes.linglart@aphp.fr.
authors.forename: Agnès
authors.initials: A
authors.lastname: Linglart
authors.affiliation: Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA. Electronic address: millan@sanfordburnham.org.
authors.forename: José Luis
authors.initials: JL
authors.lastname: Millán
authors.affiliation: Endocrinologie, Maladies Osseuses, Génétique et Gynécologie Médicale, Hôpital des Enfants, CHU de Toulouse, Toulouse Cedex 9, France. Electronic address: salles.jp@chu-toulouse.fr.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Salles
authors.affiliation: Unité de Génétique Constitutionnelle, Centre Hospitalier de Versailles, 78150 Le Chesnay, France. Electronic address: cmuti@ch-versailles.fr.
authors.forename: Christine
authors.initials: C
authors.lastname: Muti
authors.affiliation: Unité de Génétique Constitutionnelle, Centre Hospitalier de Versailles, 78150 Le Chesnay, France. Electronic address: bsimon-bouy@ch-versailles.fr.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Simon-Bouy
authors.affiliation: Unité de Génétique Constitutionnelle, Centre Hospitalier de Versailles, 78150 Le Chesnay, France. Electronic address: emornet@ch-versailles.fr.
authors.forename: Etienne
authors.initials: E
authors.lastname: Mornet
mesh_terms: D000328:Adult; D000368:Aged; D055036:Campomelic Dysplasia / Q000175:diagnosis; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D005333:Fetus; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D007014:Hypophosphatasia / Q000175:diagnosis* / Q000235:genetics* / Q000503:physiopathology; D007223:Infant; D008297:Male; D008875:Middle Aged; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D010013:Osteogenesis Imperfecta / Q000175:diagnosis; D017001:Tooth Demineralization / Q000151:congenital / Q000503:physiopathology
keywords: Differential diagnosis; Hypophosphatasia; NGS; Osteogenesis imperfecta