PKD2 and autosomal dominant polycystic kidney disease: Important cystic kidney disorders are autosomal dominant (ADPKD), autosomal recessive polycystic kidney disease (ARPKD) and nephronophthisis (NPH) [3–5] ADPKD is one of the most common Mendelian disorders with a prevalence of 1/400 to 1/1000, and typically a late-onset disease with mutations in PKD1 or PKD2 that can also be expressed as a recessive trait.