A missense mutation in the chloride/proton ClC-5 antiporter gene results in increased expression of an alternative mRNA form that lacks exons 10 and 11. Identification of seven new CLCN5 mutations in patients with Dent's disease.
Mutations in the voltage-gated chloride/proton antiporter ClC-5 gene, CLCN5, are associated with Dent's disease, an X-linked renal tubulopathy. Our interest is to identify and characterize disease-causing CLCN5 mutations, especially those that alter the splicing of the pre-mRNA. We analyzed the CLCN5 gene from nine unrelated Spanish Dent's disease patients and their relatives by DNA sequencing. Pre-mRNA splicing analysis was performed by RT-PCR. Seven new mutations were identified, consisting of three missense mutations (C219R, F273L, and W547G), one splice-site mutation (IVS-2A > G), one deletion (976delG), and two non-sense mutations (Y140X and W314X). We found that missense mutation W547G also led to increased expression of a new alternative isoform lacking exons 10 and 11 that was expressed in several human tissues. In addition, we describe another novel CLCN5 splicing variant lacking exon 11 alone, which was expressed only in human skeletal muscle. We conclude that missense mutation W547G can also alter the expression levels of a CLCN5 mRNA splicing variant. This type of mutation has not been previously described in the CLCN5 gene. Our results support the importance of a routine analysis at the pre-mRNA level of mutations that are commonly assumed to cause single amino acids alterations.
Ramos-Trujillo
Elena
E
Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain.
González-Acosta
Hilaria
H
Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain.
Flores
Carlos
C
Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain.
García-Nieto
Víctor
V
Unidad de Nefrología Pediátrica, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain.
Guillén
Encarna
E
Servicio de Pediatría, Hospital Universitario Virgen de la Arrixaca, Murcia, Spain.
Gracia
Salvador
S
Servicio de Pediatría, Hospital Universitario Virgen de la Arrixaca, Murcia, Spain.
Vicente
Carmen
C
Servicio de Pediatría, Hospital Universitario Virgen de la Arrixaca, Murcia, Spain.
Espinosa
Laura
L
Servicio de Nefrología Infantil, Hospital Universitario La Paz, Madrid, Spain.
Maseda
Maria A Fernández
MAF
Servicio de Pediatría, Hospital Virgen de la Salud, Toledo, Spain.
Santos
Fernando
F
Servicio de Nefrología Pediátrica, Hospital Universitario Central de Asturias, Oviedo, Spain.
Camacho
Juan A
JA
Sección de Nefrología, Hospital Sant Joan de Déu, Barcelona, Spain.
Claverie-Martín
Félix
F
Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain. fclamar@gobiernodecanarias.org.
D017398:Alternative Splicing / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D018118:Chloride Channels / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004252:DNA Mutational Analysis; D005091:Exons / Q000235:genetics*; D020869:Gene Expression Profiling; D006801:Humans; D007674:Kidney Diseases / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D020125:Mutation, Missense / Q000235:genetics*; D010375:Pedigree; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger; D013030:Spain
C097503:CLC-5 chloride channel; D018118:Chloride Channels; D020033:Protein Isoforms; D012333:RNA, Messenger