title: Evaluation of bone markers in hypophosphatemic rickets/osteomalacia.
abstract: N-terminal propeptide of type I procollagen (PINP) is a marker of newly formed type I collagen. However, its role in hypophosphatemic rickets/osteomalacia has not yet been established. Metabolic bone markers were examined in patients with oncogenic osteomalacia (OOM) and X-linked hypophosphatemic rickets (XLH), and in healthy controls. OOM and XLH patients were found to have hypophosphatemia secondary to elevated levels of serum fibroblast growth factor 23 (FGF-23). OOM patients had reduced levels of 1,25-dihydroxy vitamin D (1,25D) compared with XLH patients and healthy controls, despite attenuation of the reduction in these levels in the XLH patients secondary to active vitamin D supplementation. In contrast to patients with XLH, OOM patients showed a significant increase in serum PINP, which is suggestive of accelerated bone matrix formation. Bone alkaline phosphatase (BAP) and the BAP/PINP ratio were also increased in OOM but not in XLH patients, suggesting the presence of a disturbance in bone mineralization in OOM. Long-term supplementation of active form vitamin D and inorganic phosphate (IP) may have attenuated the defect in bone mineralization in the XLH patients, resulting in the normalization of PINP, BAP, and the BAP/PINP ratio. The present results suggest that, as with BAP, PINP is an appropriate metabolic bone marker in the assessment of hypophosphatemic rickets/osteomalacia.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Nagata
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Imanishi
authors.forename: Akira
authors.initials: A
authors.lastname: Ishii
authors.forename: Masafumi
authors.initials: M
authors.lastname: Kurajoh
authors.forename: Koka
authors.initials: K
authors.lastname: Motoyama
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Morioka
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Naka
authors.forename: Katsuhito
authors.initials: K
authors.lastname: Mori
authors.forename: Takami
authors.initials: T
authors.lastname: Miki
authors.forename: Masanori
authors.initials: M
authors.lastname: Emoto
authors.forename: Masaaki
authors.initials: M
authors.lastname: Inaba
mesh_terms: D000328:Adult; D000469:Alkaline Phosphatase / Q000097:blood; D015415:Biomarkers / Q000097:blood; D014408:Biomarkers, Tumor / Q000097:blood; D001842:Bone and Bones / Q000378:metabolism*; D002117:Calcitriol / Q000097:blood; D004872:Ergocalciferols / Q000097:blood; D053098:Familial Hypophosphatemic Rickets / Q000097:blood*; D005260:Female; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000097:blood; D040181:Genetic Diseases, X-Linked; D006801:Humans; D008297:Male; D008875:Middle Aged; D009372:Neoplasms, Connective Tissue / Q000097:blood*; D010018:Osteomalacia / Q000097:blood; D010257:Paraneoplastic Syndromes; D010446:Peptide Fragments / Q000097:blood*; D011347:Procollagen / Q000097:blood*
chemical_list: D015415:Biomarkers; D014408:Biomarkers, Tumor; D004872:Ergocalciferols; C000717427:FGF23 protein, human; D010446:Peptide Fragments; D011347:Procollagen; C047202:procollagen Type I N-terminal peptide; C003564:1,25-dihydroxyergocalciferol; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23; D000469:Alkaline Phosphatase; D002117:Calcitriol