title: Twelve novel HGD gene variants identified in 99 alkaptonuria patients: focus on 'black bone disease' in Italy.
abstract: Alkaptonuria (AKU) is an autosomal recessive disorder caused by mutations in homogentisate-1,2-dioxygenase (HGD) gene leading to the deficiency of HGD enzyme activity. The DevelopAKUre project is underway to test nitisinone as a specific treatment to counteract this derangement of the phenylalanine-tyrosine catabolic pathway. We analysed DNA of 40 AKU patients enrolled for SONIA1, the first study in DevelopAKUre, and of 59 other AKU patients sent to our laboratory for molecular diagnostics. We identified 12 novel DNA variants: one was identified in patients from Brazil (c.557T>A), Slovakia (c.500C>T) and France (c.440T>C), three in patients from India (c.469+6T>C, c.650-85A>G, c.158G>A), and six in patients from Italy (c.742A>G, c.614G>A, c.1057A>C, c.752G>A, c.119A>C, c.926G>T). Thus, the total number of potential AKU-causing variants found in 380 patients reported in the HGD mutation database is now 129. Using mCSM and DUET, computational approaches based on the protein 3D structure, the novel missense variants are predicted to affect the activity of the enzyme by three mechanisms: decrease of stability of individual protomers, disruption of protomer-protomer interactions or modification of residues in the region of the active site. We also present an overview of AKU in Italy, where so far about 60 AKU cases are known and DNA analysis has been reported for 34 of them. In this rather small group, 26 different HGD variants affecting function were described, indicating rather high heterogeneity. Twelve of these variants seem to be specific for Italy.
authors: Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Bratislava, Slovakia.
authors: Martina
authors: M
authors: Nemethova
authors: Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Bratislava, Slovakia.
authors: Jan
authors: J
authors: Radvanszky
authors: Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Bratislava, Slovakia.|Department of Molecular Biology, Faculty of Natural Sciences, Comenius university, Bratislava, Slovakia.
authors: Ludevit
authors: L
authors: Kadasi
authors: Department of Biochemistry, Cambridge University, Cambridge, UK.
authors: David B
authors: DB
authors: Ascher
authors: Department of Biochemistry, Cambridge University, Cambridge, UK.
authors: Douglas E V
authors: DE
authors: Pires
authors: Department of Biochemistry, Cambridge University, Cambridge, UK.
authors: Tom L
authors: TL
authors: Blundell
authors: Medical Genetics Unit, Department of Experimental and Clinical Biomedical Sciences University of Florence, Florence, Italy.
authors: Berardino
authors: B
authors: Porfirio
authors: Internal Medicine Division, Rheumatology Unit, Ospedali S. Maria Nuova e Palagi, Florence, Italy.
authors: Alessandro
authors: A
authors: Mannoni
authors: Dipartimento di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Siena, Italy.
authors: Annalisa
authors: A
authors: Santucci
authors: Dipartimento di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Siena, Italy.
authors: Lia
authors: L
authors: Milucci
authors: President of aimAKU, Associazione Italiana Malati di Alcaptonuria, Siena, Italy.
authors: Silvia
authors: S
authors: Sestini
authors: Porphyria Centre and Metabolic Rare Diseases, San Gallicano Dermatological Institute, IRCCS - IFO Rome, Rome, Italy.
authors: Gianfranco
authors: G
authors: Biolcati
authors: Porphyria Centre and Metabolic Rare Diseases, San Gallicano Dermatological Institute, IRCCS - IFO Rome, Rome, Italy.
authors: Fiammetta
authors: F
authors: Sorge
authors: Porphyria Centre and Metabolic Rare Diseases, San Gallicano Dermatological Institute, IRCCS - IFO Rome, Rome, Italy.
authors: Caterina
authors: C
authors: Aurizi
authors: Laboratoire de Biochimie et Biologie Moléculaire, Facultéde Médecine, Aix Marseille Université, Marseille, France.
authors: Robert
authors: R
authors: Aquaron
authors: Department of Pharmacology, Faculty of Medicine, Mutah University, Karak, Jordan.
authors: Mohammed
authors: M
authors: Alsbou
authors: Neurogenetics Unit, Department of Neurology School of Medicine of Ribeirão Preto, University of São Paulo, São Paulo, Brazil.
authors: Charles Marques
authors: CM
authors: Lourenço
authors: Institute of Biochemistry, Madras Medical College& Rajiv Gandhi Government General Hospital, Chennai, India.
authors: Kanakasabapathi
authors: K
authors: Ramadevi
authors: Department of Clinical Biochemistry and Metabolism, Royal Liverpool University Hospital, Liverpool, UK.
authors: Lakshminarayan R
authors: LR
authors: Ranganath
authors: Department of Musculosceletal Biology, University of Liverpool, Liverpool, UK.
authors: James A
authors: JA
authors: Gallagher
authors: PSR group B.V., 2132 HN Hoofddorp, Netherlands.
authors: Christa
authors: C
authors: van Kan
authors: Cudos B.V., 2132 HN Hoofddorp, Netherlands.
authors: Anthony K
authors: AK
authors: Hall
authors: Swedish Orphan Biovitrum AB (publ), Stockholm, Sweden.
authors: Birgitta
authors: B
authors: Olsson
authors: AKU Society, Cambridge, UK.
authors: Nicolas
authors: N
authors: Sireau
authors: AKU Society, Cambridge, UK.
authors: Hana
authors: H
authors: Ayoob
authors: AKU Society, Cambridge, UK.
authors: Oliver G
authors: OG
authors: Timmis
authors: Clinical Pharmacology, Department of Genetics, University Paris Descartes, IMAGINE, Necker Hospital, Paris, France.
authors: Kim-Hanh Le Quan
authors: KH
authors: Sang
authors: Nordic Bioscience, Herlev, Denmark.
authors: Federica
authors: F
authors: Genovese
authors: National Institute of Rheumatic Diseases, Piešťany, Slovakia.
authors: Richard
authors: R
authors: Imrich
authors: National Institute of Rheumatic Diseases, Piešťany, Slovakia.
authors: Jozef
authors: J
authors: Rovensky
authors: Department of Paediatrics, JIPMER, Puducherry, India.
authors: Rangan
authors: R
authors: Srinivasaraghavan
authors: Division of Neonatology, JIPMER, Puducherry, India.
authors: Shruthi K
authors: SK
authors: Bharadwaj
authors: Emek Medical Center, Afula, Israel.
authors: Ronen
authors: R
authors: Spiegel
authors: Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Bratislava, Slovakia.
authors: Andrea
authors: A
authors: Zatkova
mesh_terms: D000474:Alkaptonuria / Q000175:diagnosis / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D001483:Base Sequence; D001851:Bone Diseases, Metabolic / Q000175:diagnosis / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D001842:Bone and Bones / Q000201:enzymology* / Q000473:pathology; D020134:Catalytic Domain; D030541:Databases, Genetic; D005091:Exons; D005260:Female; D015870:Gene Expression; D018740:Genetic Heterogeneity; D050560:Homogentisate 1,2-Dioxygenase / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D007438:Introns; D007558:Italy; D008297:Male; D008958:Models, Molecular; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D010375:Pedigree; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D017433:Protein Structure, Secondary; D017422:Sequence Analysis, DNA
chemical_list: D050560:Homogentisate 1,2-Dioxygenase