EXOC1 and hydronephrosis: Exoc4/Sec8-/- mice initiate gastrulation but die shortly afterward (Friedrich et al., 1997), Exoc1/Sec3-null mice undergo peri-implantation lethality (Mizuno et al., 2015), and the conditional ablation of Exoc5/Sec10 leads to bilateral hydronephrosis and complete anuria in newborn mice leading to death shortly after (Fogelgren et al., 2015).