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Updated: May 30, 2026

Skeletal Phenotype Analysis of a Conditional Stat3 Deletion Mouse Model
Published on: July 3, 2020
Kbus/Idr, a mutant mouse strain with skeletal abnormalities and hypophosphatemia: identification as an allele of
Kenji Moriyama1, Atsuko Hanai, Kazuyuki Mekada
1Department of Medicine & Clinical Science, School of Pharmacy and Pharmaceutical Sciences, Mukogawa Women's University, Nishinomiya 663-8179, Japan. kemori@mukogawa-u.ac.jp
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.
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