Therefore, we investigated whether a normal phosphorus level can cause endothelial dysfunction and how the major factors involved in mineral metabolism, including serum phosphorus, parathyroid hormone (PTH), and fibroblast growth factor 23 (FGF23) levels, affect endothelial dysfunction in CKD patients, using EndoPAT and iontophoresis with LDF. This evidence concerns the gene FGF23 and endothelial dysfunction.