title: Kbus/Idr, a mutant mouse strain with skeletal abnormalities and hypophosphatemia: identification as an allele of 'Hyp'.
abstract: BACKGROUND
  The endopeptidase encoded by Phex (phosphate-regulating gene with homologies to endopeptidases linked to the X chromosome) is critical for regulation of bone matrix mineralization and phosphate homeostasis. PHEX has been identified from analyses of human X-linked hypophosphatemic rickets and Hyp mutant mouse models. We here demonstrated a newly established dwarfism-like Kbus/Idr mouse line to be a novel Hyp model.
  
  
  METHODS
  Histopathological and X-ray examination with cross experiments were performed to characterize Kbus/Idr. RT-PCR-based and exon-directed PCR screening performed to identify the presence of genetic alteration. Biochemical assays were also performed to evaluate activity of alkaline phosphatase.
  
  
  RESULTS
  Kbus/Idr, characterized by bone mineralization defects, was found to be inherited in an X chromosome-linked dominant manner. RT-PCR experiments showed that a novel mutation spanning exon 16 and 18 causing hypophosphatemic rickets. Alkaline phosphatase activity, as an osteoblast marker, demonstrated raised levels in the bone marrow of Kbus/Idr independent of the age.
  
  
  CONCLUSIONS
  Kbus mice should serve as a useful research tool exploring molecular mechanisms underlying aberrant Phex-associated pathophysiological phenomena.
authors.affiliation: Department of Medicine & Clinical Science, School of Pharmacy and Pharmaceutical Sciences, Mukogawa Women's University, Nishinomiya 663-8179, Japan. kemori@mukogawa-u.ac.jp
authors.forename: Kenji
authors.initials: K
authors.lastname: Moriyama
authors.forename: Atsuko
authors.initials: A
authors.lastname: Hanai
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Mekada
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yoshiki
authors.forename: Katsueki
authors.initials: K
authors.lastname: Ogiwara
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kimura
authors.forename: Takayuki
authors.initials: T
authors.lastname: Takahashi
mesh_terms: D000469:Alkaline Phosphatase / Q000097:blood; D000818:Animals; D005799:Genes, Dominant / Q000235:genetics; D050172:Genes, X-Linked / Q000235:genetics; D017674:Hypophosphatemia / Q000235:genetics* / Q000473:pathology; D051379:Mice; D008817:Mice, Mutant Strains; D009139:Musculoskeletal Abnormalities / Q000000981:diagnostic imaging / Q000235:genetics*; D053402:PHEX Phosphate Regulating Neutral Endopeptidase / Q000235:genetics*; D010641:Phenotype; D011859:Radiography; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000469:Alkaline Phosphatase; D053402:PHEX Phosphate Regulating Neutral Endopeptidase; C506232:Phex protein, mouse