Interestingly, these patterns of calcium handling in the Trpv5682P/+, Trpv5682P/682P and Trpv5-/- mice, are similar to those found in many patients with idiopathic hypercalciuria, who have renal hypercalciuria in association with elevated concentrations of 1,25-dihydroxyvitamin D3, but with normocalcaemia (or mild hypocalcaemia) and normal (or suppressed) plasma PTH concentrations [14], [21]. Here, PTH is linked to idiopathic hypercalciuria.