PKHD1 and autosomal recessive polycystic kidney disease: Moreover, there is evidence in ARPKD mouse models with variants in other genes that the disease is modified; for example, co-inheritance of mutations in Pkhd1 and Pkd1 worsens the phenotype; this correlates in humans where a mutation in the other ADPKD gene (PKD2) also worsen the kidney manifestation [60,61].