Most studies reported that OPN expression is elevated in urolithiasis, and also in acute and chronic kidney diseases, and in renal allograft dysfunction.
The crystal spherulite formations obtained in vitro when using the most phosphorylated form of OPN-ASARM peptide at a high concentration, resembled crystal morphologies observed in vivo in a rat model of urolithiasis, in which crystal deposits in the kidney contain abundant OPN as revealed by immunogold labeling.
With regard to genetic factors, studies show that single nucleotide polymorphisms in genes encoding calcium-sensing receptor, vitamin D receptor and osteopontin are correlated with urolithiasis.
Overall, a significantly increased risk of urolithiasis was associated with OPN gene polymorphism rs1126616 for all the genetic models except recessive model.