Fibroblast growth factor 23 levels in cord and peripheral blood during early neonatal period as possible predictors of affected offspring of X-linked hypophosphatemic rickets: report of three female cases from two pedigrees

J Pediatr Endocrinol Metab. 2023 Jun 22;36(8):786-790. doi: 10.1515/jpem-2023-0120. Print 2023 Aug 28.

Abstract

Objectives: The role of serum fibroblast growth factor 23 (FGF23) level in early neonatal period on the diagnosis of X-linked hypophosphatemic rickets (XLH) remains unclear.

Case presentation: Two female patients from the first pedigree had an affected mother, and the other female from the second pedigree had an affected father. In all three cases, FGF23 levels were high in cord blood and peripheral blood at day 4-5. Additionally, the FGF23 levels considerably increased from birth to day 4-5. We identified a PHEX pathogenic variant and initiated treatment during infancy in each case.

Conclusions: In neonates with a parent diagnosed as PHEX-associated XLH, FGF23 in cord blood and peripheral blood at day 4-5 may be useful markers for predicting the presence of XLH.

Keywords: PHEX; X-linked hypophosphatemic rickets; cord blood; fibroblast growth factor 23; neonatal period.

Publication types

  • Case Reports

MeSH terms

  • Biomarkers* / analysis
  • Biomarkers* / blood
  • Familial Hypophosphatemic Rickets* / blood
  • Familial Hypophosphatemic Rickets* / genetics
  • Female
  • Fetal Blood / chemistry
  • Fibroblast Growth Factor-23* / analysis
  • Fibroblast Growth Factor-23* / blood
  • Humans
  • Infant, Newborn
  • PHEX Phosphate Regulating Neutral Endopeptidase / genetics

Substances

  • FGF23 protein, human
  • Biomarkers
  • PHEX protein, human
  • PHEX Phosphate Regulating Neutral Endopeptidase
  • Fibroblast Growth Factor-23