title: [Chronic bone pain due to raised FGF23 production? The importance of determining phosphate levels].
abstract: Hypophosphatemia is an important finding in the evaluation of patients with chronic bone pain. Fibroblast-growth factor 23 (FGF23) plays a role in the differential diagnosis of hypophosphatemia. A 34-year-old man had progressive pain in both shoulders and hips due to hypophosphatemic osteomalacia. He had elevated FGF23 levels, induced by a FGF23-producing tumour in the right acetabulum. Thus, he had tumour-induced hypophosphatemic osteomalacia. A 50-year-old man had had bowed legs and joint pains since his youth due to osteomalacia. Several family members also had osteomalacia. His phosphate concentration was low. Genetic testing revealed a mutation on the PHEX gene which results in high FGF23 levels. Thus, he had X-linked hereditary hypophosphatemic osteomalacia. In patients with bone pain, the measurement of a phosphate concentration is important. In renal phosphate loss, the measurement of FGF23 is an important next step if parathormone concentrations are low or normal.
authors.affiliation: VUmc, Afd. Interne Geneeskunde, Amsterdam, the Netherlands. rt.dejongh@vumc.nl
authors.forename: Renate T
authors.initials: RT
authors.lastname: de Jongh
authors.forename: Marc G
authors.initials: MG
authors.lastname: Vervloet
authors.forename: Nathalie
authors.initials: N
authors.lastname: Bravenboer
authors.forename: Annemieke C
authors.initials: AC
authors.lastname: Heijboer
authors.forename: Martin
authors.initials: M
authors.lastname: den Heijer
authors.forename: Paul
authors.initials: P
authors.lastname: Lips
mesh_terms: D000328:Adult; D001859:Bone Neoplasms / Q000097:blood / Q000150:complications* / Q000175:diagnosis; D003937:Diagnosis, Differential; D053098:Familial Hypophosphatemic Rickets / Q000097:blood / Q000175:diagnosis*; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000097:blood*; D040181:Genetic Diseases, X-Linked; D006801:Humans; D017674:Hypophosphatemia / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D010018:Osteomalacia / Q000097:blood / Q000175:diagnosis* / Q000209:etiology
chemical_list: C000717427:FGF23 protein, human; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23