[Phosphate metabolism and iron deficiency]

Area of Science:

• Endocrinology
• Genetics
• Nephrology

Background:

• Autosomal dominant hypophosphatemic rickets (ADHR) is linked to FGF23 gain-of-function mutations, impairing its cleavage.
• Fibroblast growth factor 23 (FGF23) regulates phosphate and vitamin D metabolism.
• Iron deficiency is an environmental factor exacerbating ADHR by stimulating FGF23 production.

Purpose of the Study:

• To investigate the role of iron status in ADHR pathophysiology.
• To evaluate the effect of iron treatment on FGF23 and phosphate levels in CKD patients.

Main Methods:

• Review of ADHR pathophysiology related to FGF23 mutations and iron deficiency.
• Analysis of FGF23 elevation in chronic kidney disease (CKD) patients with iron deficiency.
• Clinical observation of ferric citrate hydrate treatment in non-dialysis CKD patients.

Main Results:

• Iron deficiency stimulates FGF23 expression, contributing to hypophosphatemia in ADHR.
• FGF23 levels are elevated in iron-deficient CKD patients.
• Ferric citrate hydrate treatment significantly reduced serum phosphate and FGF23 in CKD patients.

Conclusions:

• Iron deficiency is a key factor in ADHR pathogenesis and FGF23 elevation.
• Iron repletion therapy may be beneficial for managing phosphate and FGF23 levels in ADHR and CKD patients.