Characterization of renal chloride channel (CLCN5) mutations in Dent's disease.
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.
Yamamoto
Katsusuke
K
MRC Molecular Endocrinology Group, Hammersmith Hospital, London, United Kingdom.
Cox
Jeremy P D T
JPDT
MRC Molecular Endocrinology Group, Hammersmith Hospital, London, United Kingdom.
Friedrich
Thomas
T
ZMNH Centre for Molecular Neurobiology, University of Hamburg, Germany.
Christie
Paul T
PT
MRC Molecular Endocrinology Group, Hammersmith Hospital, London, United Kingdom.|Nuffield Department of Medicine, John Radcliffe Hospital, Oxford, United Kingdom.
Bald
Martin
M
Department of Paediatric Nephrology, University of Essen, Germany.
Houtman
Peter N
PN
Department of Paediatrics, Leicester Royal Infirmary, United Kingdom.
Lapsley
Marta J
MJ
Department of Chemical Pathology and Metabolism, St Helier Hospital, Surrey, United Kingdom.
Patzer
Ludwig
L
Children's Hospital "Jussuf Ibrahim," Friedrich-Schiller University, Jena, Germany.
Tsimaratos
Michel
M
Department of Paediatric Nephrology, Children's Hospital of the Timone, Marseille, France.
Van't Hoff
William G
WG
Department of Paediatric Nephrology, Great Ormond Street Hospital, London, United Kingdom.
Yamaoka
Kanji
K
Department of Paediatrics, Osaka Prefectural Hospital, Osaka, Japan.
Jentsch
Thomas J
TJ
ZMNH Centre for Molecular Neurobiology, University of Hamburg, Germany.
Thakker
Rajesh V
RV
MRC Molecular Endocrinology Group, Hammersmith Hospital, London, United Kingdom.|Nuffield Department of Medicine, John Radcliffe Hospital, Oxford, United Kingdom.
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
C097503:CLC-5 chloride channel; D018118:Chloride Channels; D004247:DNA