Here, we take the opportunity to share further longitudinal, observational data on the original ADH case that first demonstrated the reversibility of hypophosphatemia on oral iron therapy.12 The girl had presented with hypophosphatemic rickets and iron deficiency at age 26 months and was found to have a typical R179Q mutation in FGF23. Rickets responded well to conventional therapy. Here, FGF23 is linked to hypophosphatemia.