HOXB7 and Hydroureter: Although the current ShhCreERT2/flox mice with TM treatment at later stages (e.g., E13.5) did not display prominent phenotypes, the Hoxb7-Cre; Shhflox/− mice, which are conditional mutants of the Shh gene in the mesonephric duct from E9.5, show delayed differentiation of ureteral smooth muscle, hydroureter and hydronephrosis phenotypes [2].