title: Hungry bone syndrome and normalisation of renal phosphorus threshold after total parathyroidectomy for tertiary hyperparathyroidism in X-linked hypophosphataemia: a case report.
abstract: BACKGROUND
  This is the first report of which the authors are aware to describe this c.2166delinsGG mutation in X-linked hypophosphataemia and to describe normalisation of renal threshold for phosphate excretion after parathyroidectomy for tertiary hyperparathyroidism in X-linked hypophosphataemia.
  
  
  METHODS
  We present the case of a 34-year-old Caucasian woman with X-linked hypophosphataemia. She developed tertiary hyperparathyroidism with markedly high bone turnover requiring total parathyroidectomy and had prolonged requirement for intravenous calcium infusion after surgery. She had a novel mutation in her phosphate-regulating gene with homologies to endopeptidases on the X-chromosome and had an unusual degree of dependence on phosphate supplementation. Prior to operative intervention she had a trial of cinacalcet that improved bone turnover markers when used in isolation but which led to a paradoxical rise in parathyroid hormone levels when given with phosphate supplementation. After correction of hungry bone syndrome, the renal phosphorus threshold normalised as a manifestation of hypoparathyroid state despite marked elevation in level of fibroblast growth factor 23.
  
  
  CONCLUSIONS
  This case illustrates the risk of tertiary hyperparathyroidism as a complication of treatment for hypophosphataemia; it highlights the morbidity associated with hungry bone syndrome and provides novel insight into renal handling of phosphorus.
authors.forename: Rachel K
authors.initials: RK
authors.lastname: Crowley
authors.forename: Mark
authors.initials: M
authors.lastname: Kilbane
authors.forename: Thomas Fj
authors.initials: TF
authors.lastname: King
authors.forename: Michelle
authors.initials: M
authors.lastname: Morrin
authors.forename: Myra
authors.initials: M
authors.lastname: O'Keane
authors.affiliation: Department of Endocrinology, St, Vincent's University Hospital, Dublin, Ireland. mjmckenn@iol.ie.
authors.forename: Malachi J
authors.initials: MJ
authors.lastname: McKenna