PKD2 and polycystic kidney disease: Mouse models of attenuating Pkd2 expression by conditional genetic repression faithfully recapitulate the polycystic kidney phenotype (Happé and Peters, 2014; Ma et al., 2013; Wilson, 2008; Wu et al., 1998), whereas complete genetic deletion of Pkd2 causes embryonic lethality and kidney cyst development in utero (Menezes and Germino, 2013; Wu et al., 2000).