Serum α-Klotho as a Potential Biomarker in Pediatric Urolithiasis

Background: Urolithiasis is an emerging problem in the pediatric population, with multifactorial etiology involving genetic, metabolic, and environmental factors. The α-Klotho protein, known for its role in mineral homeostasis and oxidative stress modulation, has been implicated in adult urolithiasis, but its relevance in children remains unexplored. Aim of the study was to assess serum α-Klotho levels in children with urinary stone disease and evaluate its potential as a biomarker associated with clinical features and risk of recurrence. Methods: A prospective study was conducted in 40 pediatric patients with urolithiasis and 40 healthy controls. Serum α-Klotho levels were measured using ELISA. Additional parameters included calcium-phosphate metabolism, 24-hour urine collections, treatment type, recurrence, and modifiable risk factors. Results: Serum α-Klotho levels were significantly lower in children with urolithiasis compared to controls (1622 vs. 2184 pg/ml, p  = 0.017). Lower α-Klotho levels were associated with positive family history ( p  = 0.049), recurrence of renal colic ( p  = 0.001), and need for surgical intervention during recurrence ( p  = 0.029). α-Klotho levels positively correlated with serum phosphate ( p  = 0.045) but showed no significant relationship with other laboratory results. Increased physical activity was associated with higher Klotho levels ( p  = 0.023), while no association was found with diet or fluid intake. Conclusions: This is the first study to investigate α-Klotho in pediatric urolithiasis. Our findings suggest that reduced serum α-Klotho levels may precede metabolic abnormalities and correlate with recurrence risk, supporting its potential role as an early biomarker in children with urinary stone disease.