Since we were able to demonstrate that polycystin-2poreL1 enters the primary cilium, a trafficking defect, as has been shown for other polycystin-2 mutant proteins (Cai et al., 2014; Walker et al., 2019; Yoshiba et al., 2012), is unlikely to explain cyst formation in our case. The gene discussed is PKD2; the disease is cyst.