LRP2 and Hypercalciuria: Renal defects of megalin knockout (KO) mice (Leheste et al., 2003, 1999) include phosphaturia, hypercalciuria, and proteinuria, due to loss of megalin ligands such as RBP, DBP and albumin (Bockenhauer et al., 2008; Bothwell et al., 2011).