PKHD1 and autosomal recessive polycystic kidney disease: Autosomal dominant PKD (ADPKD; MIM 173900) is caused by mutations in the PKD1 or PKD2 genes [2–5] and autosomal recessive PKD (ARPKD; MIM 263200) results from mutations in the PKHD1 gene [6, 7].