title: Molecular analysis of patients with type III Bartter syndrome: picking up large heterozygous deletions with semiquantitative PCR.
abstract: Type III Bartter syndrome (BS) (OMIM607364) is caused by mutations in the basolateral chloride channel CIC-Kb gene (CLCNKB). The CLCNKB gene is sometimes reported as having a large deletion mutation, but all cases reported previously were large homozygous deletions and a large heterozygous deletion is impossible to detect by direct sequencing. This report concerns a genetic analysis of five Japanese patients with type III BS. To identify the mutations, we used polymerase chain reaction (PCR) and direct sequencing. To detect large heterozygous deletion mutations of the CLCNKB gene, we conducted semiquantitative PCR amplification using capillary electrophoresis. The result was that four mutations were identified, comprising one novel 2-bp deletion mutation, an entire heterozygous deletion, and a heterozygous deletion mutation of exons 1 and 2. The nonsense mutation W610X was detected in all patients, and this mutation is likely to constitute a founder effect in Japan. Capillary electrophoresis is a new method and extremely useful for detecting large heterozygous deletions, and should be used to examine type III BS cases in whom only a heterozygous mutation has been detected by direct sequencing. This is the first report to identify large heterozygous deletion mutations in the CLCNKB gene in patients with type III BS.
authors.affiliation: Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, 6500017, Japan. nozu@med.kobe-u.ac.jp
authors.forename: Kandai
authors.initials: K
authors.lastname: Nozu
authors.forename: Xue Jun
authors.initials: XJ
authors.lastname: Fu
authors.forename: Koichi
authors.initials: K
authors.lastname: Nakanishi
authors.forename: Norishige
authors.initials: N
authors.lastname: Yoshikawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kaito
authors.forename: Kyoko
authors.initials: K
authors.lastname: Kanda
authors.forename: Rafal Przybyslaw
authors.initials: RP
authors.lastname: Krol
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Miyashita
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Kamitsuji
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Kanda
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Kenichi
authors.initials: K
authors.lastname: Satomura
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Shimizu
authors.forename: Kazumoto
authors.initials: K
authors.lastname: Iijima
authors.forename: Masafumi
authors.initials: M
authors.lastname: Matsuo
mesh_terms: D000293:Adolescent; D000328:Adult; D001477:Bartter Syndrome / Q000235:genetics*; D002675:Child, Preschool; D018118:Chloride Channels / Q000235:genetics; D004252:DNA Mutational Analysis; D005260:Female; D005819:Genetic Markers; D006239:Haplotypes; D006579:Heterozygote; D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods*; D011110:Polymorphism, Genetic; D017384:Sequence Deletion
chemical_list: C412733:CLCNKB protein, human; D018118:Chloride Channels; D005819:Genetic Markers