PKD1 and Kidney Cyst: The onset of kidney cyst development in adult mice following conditional inactivation of Pkd1 or the intraflagellar transport protein kinesin, KIF3a (required for cilia formation), progresses well into adulthood, in analogy to the late progression of ADPKD in humans (Davenport et al., 2007; Piontek et al., 2007; Shibazaki et al., 2008).