Expression of FGF23 and α-KLOTHO in Normal Human Kidney Development and Congenital Anomalies of the Kidney and Urinary Tract (CAKUT)

Congenital anomalies of the kidney and urinary tract (CAKUT) are a major cause of pediatric renal failure, but the molecular mechanisms driving these conditions are not yet fully understood. Fibroblast Growth Factor 23 (FGF23) and its co-receptor α-KLOTHO play crucial roles in regulating calcium and phosphate homeostasis in adult kidneys, but their roles in kidney development and the pathogenesis of CAKUT remain unclear. Because of that, we analyzed the spatial and temporal expression of FGF23 and α-KLOTHO in normal fetal kidney development and CAKUT using an immunofluorescence technique. Our results demonstrate a dynamic pattern of FGF23 and α-KLOTHO expression in healthy kidney development, with FGF23 levels decreasing and α-KLOTHO levels increasing with gestational age. Also, we showed that FGF23 expression was significantly reduced in horseshoe (HKs) and duplex kidneys (DKs), while α-KLOTHO expression remained unchanged across all CAKUT conditions. Based on our results, we suggest that altered FGF23 expression in CAKUT contributes to disease pathogenesis and may represent a potential therapeutic target.