PKD2 and autosomal dominant polycystic kidney disease: To first biochemically evaluate the impact of ADPKD-associated R654X and R803X truncation variants heterologously, we expressed N-terminally HA-tagged variant channels (HA-PKD2) in PKD1null:PKD2null HEK293 cell lines genetically edited with the CRISPR/Cas9 method (23).