Tyr1062Ret mouse mutants, characterized by aberrant phosphatidylinositol 3-kinase (PI3K)/Akt and rat sarcoma (Ras)/extracellular-signal-regulated kinase (Erk) 1/2 signaling, exhibit more severe defects, which include renal agenesis, hypodysplasia, and ureteral defects, whereas Tyr1015Ret mutans, characterized by aberrant phospholipase C (PLC) γ signaling, manifest renal hypodysplasia and ureteral defects, but not renal agenesis [25]. This evidence concerns the gene AKT1 and renal agenesis.