Hypophosphatemia in kidney stone formers.

PURPOSE OF REVIEW: Hypophosphatemia is frequently observed among kidney stone formers, yet the mechanisms linking phosphate homeostasis to nephrolithiasis remain nebulous. Recent advances in clinical genetics have led to renewed interest in phosphate metabolism as both a stone risk factor and a therapeutic target. This review summarizes the evolving understanding of disordered phosphate homeostasis in nephrolithiasis and highlights recent developments.

RECENT FINDINGS: Stone formers frequently exhibit lower serum phosphate and disproportionately high kidney phosphate losses, largely driven by reduced tubular reabsorption rather than dietary intake or dysregulation of hormonal pathways. Emerging data implicate variants in proximal tubule phosphate transporter genes as underlying this phenomenon. Phosphate supplementation has demonstrated benefit in prevention of stone recurrence via reduction of urinary calcium though therapeutic response is variable, perhaps due to genetic differences. Recent studies have linked genetic variants in these transporters to stone risk.

SUMMARY: Understanding of tubular phosphate handling and its underlying genetics in nephrolithiasis suggests that genetic screening and personalized approaches to therapies such as phosphate supplementation will improve clinical outcomes. Ongoing research into the association between transporter variants and clinical outcomes heralds a new era of individualized stone therapy.