title: Mutational analyses of the ATP6V1B1 and ATP6V0A4 genes in patients with primary distal renal tubular acidosis.
abstract: BACKGROUND
  Mutations in the ATP6V1B1 and the ATP6V0A4 genes cause primary autosomal-recessive distal renal tubular acidosis (dRTA). Large deletions of either gene in patients with dRTA have not been described.
  
  
  METHODS
  The ATP6V1B1 and ATP6V0A4 genes were directly sequenced in 11 Japanese patients with primary dRTA from nine unrelated kindreds. Large heterozygous deletions were analyzed by quantitative real-time polymerase chain reaction (PCR). The clinical features of the 11 patients were also investigated.
  
  
  RESULTS
  Novel mutations in the ATP6V1B1 gene were identified in two kindreds, including frameshift, in-frame insertion and nonsense mutations. Large deletions in the ATP6V0A4 gene were identified in two kindreds. Exon 15 of ATP6V0A4 was not amplified in one patient, with a long PCR confirming compound heterozygous deletions of 3.7- and 6.9-kb nucleotides, including all of exon 15. Direct DNA sequencing revealed a heterozygous frameshift mutation in ATP6V0A4 in another patient, with quantitative real-time PCR indicating that all exons up to exon 8 were deleted in one allele. Clinical investigation showed that four of the six patients with available clinical data presented with hyperammonemia at onset.
  
  
  CONCLUSIONS
  To our knowledge, these dRTA patients are the first to show large deletions involving one or more entire exons of the ATP6V0A4 gene. Quantitative PCR amplification may be useful in detecting heterozygous large deletions. These results expand the spectrum of mutations in the ATP6V0A4 and ATP6V1B1 genes associated with primary dRTA and provide insight into possible structure-function relationships.
authors.affiliation: Department of Pediatrics, Faculty of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Miura
authors.forename: Takashi
authors.initials: T
authors.lastname: Sekine
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Takahashi
authors.forename: Junko
authors.initials: J
authors.lastname: Takita
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Harita
authors.forename: Kentaro
authors.initials: K
authors.lastname: Ohki
authors.forename: Myoung-Ja
authors.initials: MJ
authors.lastname: Park
authors.forename: Yasuhide
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Asako
authors.initials: A
authors.lastname: Tajima
authors.forename: Masayuki
authors.initials: M
authors.lastname: Ishihara
authors.forename: Masataka
authors.initials: M
authors.lastname: Hisano
authors.forename: Miki
authors.initials: M
authors.lastname: Murai
authors.forename: Takashi
authors.initials: T
authors.lastname: Igarashi
mesh_terms: D000141:Acidosis, Renal Tubular / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004252:DNA Mutational Analysis; D005091:Exons / Q000235:genetics*; D005190:Family; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D011379:Prognosis; D060888:Real-Time Polymerase Chain Reaction; D025262:Vacuolar Proton-Translocating ATPases / Q000235:genetics*; D055815:Young Adult
chemical_list: C509766:ATP6V1B1 protein, human; C490181:ATP6V0A4 protein, human; D025262:Vacuolar Proton-Translocating ATPases
keywords: ATP6V0A4; ATP6V1B1; autosomal-recessive distal renal tubular acidosis; hyperammonemia; large deletions