title: Characterization of renal chloride channel (CLCN5) mutations in Dent's disease.
abstract: Dent's disease is an X-linked renal tubular disorder characterized by low molecular weight proteinuria, hypercalciuria, nephrocalcinosis, nephrolithiasis, and renal failure. The disease is caused by mutations in a renal chloride channel gene, CLCN5, which encodes a 746 amino acid protein (CLC-5), with 12 to 13 transmembrane domains. In this study, an additional six unrelated patients with Dent's disease were identified and investigated for CLCN5 mutations by DNA sequence analysis of the 11 coding exons of CLCN5. This revealed six mutations: four frameshift deletions involving codons 392, 394, 658, and 728, one nonsense mutation (Tyr617Stop), and an A to T transversion at codon 601 that would result in either a missense mutation (Asp601Val) or creation of a novel donor splice site. These mutations were confirmed by restriction endonuclease or sequence-specific oligonucleotide hybridization analysis and were not common polymorphisms. The frameshift deletions and nonsense mutation predict truncated and inactivated CLC-5. The effects of the putative missense Asp601Val mutant CLC-5 were assessed by heterologous expression in Xenopus oocytes, and this revealed a chloride conductance that was similar to that observed for wild-type CLC-5. However, an analysis of the mutant CLCN5 transcripts revealed utilization of the novel donor splice site, resulting in a truncated CLC-5. Thus, all of the six mutations are likely to result in truncated CLC-5 and a loss of function, and these findings expand the spectrum of CLCN5 mutations associated with Dent's disease.
authors.affiliation: MRC Molecular Endocrinology Group, Hammersmith Hospital, London, United Kingdom.
authors.forename: Katsusuke
authors.initials: K
authors.lastname: Yamamoto
authors.affiliation: MRC Molecular Endocrinology Group, Hammersmith Hospital, London, United Kingdom.
authors.forename: Jeremy P D T
authors.initials: JPDT
authors.lastname: Cox
authors.affiliation: ZMNH Centre for Molecular Neurobiology, University of Hamburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Friedrich
authors.affiliation: MRC Molecular Endocrinology Group, Hammersmith Hospital, London, United Kingdom.|Nuffield Department of Medicine, John Radcliffe Hospital, Oxford, United Kingdom.
authors.forename: Paul T
authors.initials: PT
authors.lastname: Christie
authors.affiliation: Department of Paediatric Nephrology, University of Essen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Bald
authors.affiliation: Department of Paediatrics, Leicester Royal Infirmary, United Kingdom.
authors.forename: Peter N
authors.initials: PN
authors.lastname: Houtman
authors.affiliation: Department of Chemical Pathology and Metabolism, St Helier Hospital, Surrey, United Kingdom.
authors.forename: Marta J
authors.initials: MJ
authors.lastname: Lapsley
authors.affiliation: Children's Hospital "Jussuf Ibrahim," Friedrich-Schiller University, Jena, Germany.
authors.forename: Ludwig
authors.initials: L
authors.lastname: Patzer
authors.affiliation: Department of Paediatric Nephrology, Children's Hospital of the Timone, Marseille, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Tsimaratos
authors.affiliation: Department of Paediatric Nephrology, Great Ormond Street Hospital, London, United Kingdom.
authors.forename: William G
authors.initials: WG
authors.lastname: Van't Hoff
authors.affiliation: Department of Paediatrics, Osaka Prefectural Hospital, Osaka, Japan.
authors.forename: Kanji
authors.initials: K
authors.lastname: Yamaoka
authors.affiliation: ZMNH Centre for Molecular Neurobiology, University of Hamburg, Germany.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Jentsch
authors.affiliation: MRC Molecular Endocrinology Group, Hammersmith Hospital, London, United Kingdom.|Nuffield Department of Medicine, John Radcliffe Hospital, Oxford, United Kingdom.
authors.forename: Rajesh V
authors.initials: RV
authors.lastname: Thakker
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D001483:Base Sequence / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D018118:Chloride Channels / Q000235:genetics* / Q000378:metabolism; D004247:DNA / Q000235:genetics; D016368:Frameshift Mutation; D017353:Gene Deletion; D015870:Gene Expression; D006801:Humans; D007223:Infant; D007668:Kidney / Q000378:metabolism*; D007674:Kidney Diseases / Q000235:genetics*; D007684:Kidney Tubules; D009154:Mutation / Q000235:genetics*; D020125:Mutation, Missense; D009865:Oocytes / Q000502:physiology; D010375:Pedigree; D014981:Xenopus / Q000235:genetics
chemical_list: C097503:CLC-5 chloride channel; D018118:Chloride Channels; D004247:DNA