Bone Abstracts

Objectives: X-linked hypophosphatemia (XLH) is a rare genetic disorder of phosphate metabolism caused by mutations in the PHEX gene. This pilot study aims to apply novel imaging techniques to asses the musculoskeletal phenotype of XLH patients by bidirectional axial transmission (BDAT) ultrasound, magnetic resonance spectroscopy (MRS) and high resolution peripheral quantitative computed tomography (HR-pQCT).Methods: BDAT bone ultrasound of the radius and...

Objective: We constructed height growth curves for children with XLH from birth to early adolescence, a majority of whom received conventional therapy consisting of multiple daily doses of oral phosphate and active vitamin D.Methods: Growth data from four clinical studies were pooled to construct the growth curves. UX023-CL002 was an observational, retrospective chart review of 103 children with XLH, 1–14 years of age. Pre-treatment data were collec...

Objectives: XLH features renal phosphate (Pi) wasting, hypophosphatemia, rickets, and skeletal deformities from elevated circulating levels of fibroblast growth factor 23 (FGF23). KRN23, an investigational fully human monoclonal antibody, binds FGF23 and inhibits its action. Our Phase 2 study of KRN23 in XLH children (ages 5–12 years) is demonstrating improvements in serum Pi and rickets. Here we present our Phase 2 trial evaluating the efficacy and safety of KRN23 in you...

see PP59....

Mammalian target of rapamycin (mTOR) is a serine–threonine kinase that plays a central role in a number of key cellular pathways that have been previously implicated in bone formation. mTOR mediates these diverse roles by forming two multi-protein complexes, mTORC1 and mTORC2, each of which is defined by unique proteins raptor and rictor respectively.Studies from our laboratory have previously demonstrated that inhibition of mTORC1 increases the ost...

Sclerostin is a major negative regulator of osteoblastic activity. Serum sclerostin has a weak positive association with BMD but contradictory results have been described concerning associations with fractures. These contradictions could be explained by the fact that serum sclerostin does not reflect its action in bone. In this study we question whether serum sclerostin is associated with its expression in bone. In addition we aimed to detect associations between sclerostin in...

Objective: The aim of this study is to compare the bone health index (BHI) for healthy Swiss children born in 1955 with healthy Swiss children born a generation later.Method: BHI is derived from the cortical thickness in the three middle metacarpals. It is determined with the BoneXpert medical device, which automatically analyses a standard bone age hand radiograph. The measurement result is independent of the sharpness of the image. The image data are f...

Objective: The BoneXpert method for automated bone age determination from hand X-rays also determines the cortical thickness T and the bone width W in the three middle metacarpals. From these, the method derives the cortical area A=π W T (1 – T/W), the metacarpal index MCI =A/(WW) and the Bone Health Index. Recently, the method has been extended down to new-borns, and the aim of this study is to report reference curves for these bone measures.M...

Biographical DetailsBonny SpeckerDr Bonny Specker is currently Director and Chair of the E.A. Martin Program in Human Nutrition at South Dakota State University. Prior to moving to SDSU in 1997, she was at the University of Cincinnati and Cincinnati Children’s Hospital Medical Center where she received her PhD in Epidemiology and spent 15 years...

see PP137....