HNF1B and renal hypoplasia: Mutations in HNF1B cause a pleotropic set of GU anomalies, including CAKUT and various forms of renal cystic disease (e.g., hyperechogenic kidneys (phenocopying ARPKD), multicystic kidney disease, renal agenesis, renal hypoplasia, cystic dysplasia, and hyperuricemic tubulointerstitial nephropathy (23–25).