Autosomal-dominant polycystic kidney disease (ADPKD) caused primarily by variants in polycystins 1 (PKD1) and 2 (PKD2) is also a ciliopathy; however, along with ARPKD, it falls outside the scope of this review, as cysts are the principal feature. This evidence concerns the gene PKD2 and autosomal dominant polycystic kidney disease.