GREB1L and renal hypodysplasia/aplasia 3: Renal hypodysplasia/aplasia-3 (RHDA3), as the most severe end of the spectrum of congenital anomalies of the kidney and urinary tract, is mainly caused by mutations in GREB1L. However, the mutations in GREB1L identified to date only explain a limited proportion of RHDA3 cases, and the mechanism of GREB1L mutations causing RHDA3 is unclear.