Abstract

CONTEXT: The previous studies suggested a possible increased risk of hypercalcaemia and reduced bone mineral density (BMD) in Williams' syndrome (WS). However, an extensive study regarding bone metabolism has never been performed.

OBJECTIVE: To investigate bone health in young adults with WS.

DESIGN: Cross-sectional study.

SETTINGS: Endocrinology and Metabolic Diseases and Medical Genetic Units.

PATIENTS: 29 WS young adults and 29 age- and sex-matched controls.

MAIN OUTCOME MEASURES: In all subjects, calcium, phosphorus, bone alkaline phosphatase (bALP), parathyroid hormone (PTH), 25-hydroxyvitamin D (25OHVitD), osteocalcin (OC), carboxyterminal cross-linking telopeptide of type I collagen (CTX), 24-h urinary calcium and phosphorus, femoral-neck (FN) and lumbar-spine (LS) BMD and vertebral fractures (VFx) were assessed. In 19 patients, serum fibroblast growth factor-23 (FGF23) levels were measured.

RESULTS: WS patients showed lower phosphorus (3.1 ± 0.7 vs 3.8 ± 0.5 mg/dL, p = 0.0001) and TmP/GFR (0.81 ± 0.32 vs 1.06 ± 0.25 mmol/L, p = 0.001), and an increased prevalence (p = 0.005) of hypophosphoremia (34.5 vs 3.4%) and reduced TmP/GFR (37.9 vs 3.4%). Moreover, bALP (26.3 ± 8.5 vs 35.0 ± 8.0 U/L), PTH (24.5 ± 12.6 vs 33.7 ± 10.8 pg/mL), OC (19.4 ± 5.3 vs 24.5 ± 8.7 ng/mL), and FN-BMD (- 0.51 ± 0.32 vs 0.36 ± 0.32) were significantly lower (p < 0.05), while CTX significantly higher (401.2 ± 169.3 vs 322.3 ± 122.4 pg/mL, p < 0.05). Serum and urinary calcium and 25OHVitD levels, LS-BMD and VFx prevalence were comparable. No cases of hypercalcemia and suppressed FGF23 were documented. Patients with low vs normal phosphorus and low vs normal TmP/GFR showed comparable FGF23 levels. FGF23 did not correlate with phosphorus and TmP/GFR values.

CONCLUSIONS: Adult WS patients have reduced TmP/GFR, inappropriately normal FGF23 levels and an uncoupled bone turnover with low femoral BMD.

Original languageEnglish
Pages (from-to)337-344
Number of pages8
JournalJournal of Endocrinological Investigation
Volume42
Issue number3
DOIs
Publication statusPublished - Mar 2019

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Keywords

  • Adult
  • Biomarkers/analysis
  • Bone Density
  • Bone Diseases, Metabolic/etiology
  • Bone Remodeling
  • Case-Control Studies
  • Cross-Sectional Studies
  • Female
  • Fibroblast Growth Factors/metabolism
  • Follow-Up Studies
  • Humans
  • Hypophosphatemia/etiology
  • Male
  • Parathyroid Hormone/metabolism
  • Prognosis
  • Williams Syndrome/complications
  • Young Adult

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