In the present study, we used Npt2a-/- mice to model these disorders. Renal mineral deposits in Npt2a-/- mice are found at intraluminal and interstitial sites, they contain calcium, phosphorus and osteopontin, and it has been suggested that they ultrastructurally resemble the composition of Randall’s plaques [33, 34]. The extent of renal mineralization is highest between newborn and weaning age Npt2a-/- mice . Mineralization resolves subsequently on 0.3–0.6% dietary phosphate, but persists beyond weaning age when diets are supplemented with 1.65% phosphate  or 1.2% phosphate [12, 36]. Ablation of 25(OH)-vitamin D-1-alpha hydroxylase (Cyp27a1) prevents renal mineralization, as shown in Cyp27a1-/-/Npt2a-/- double-knockout mice .