The observed discrepancies in the Wnt5a and Vangl2 mRNA levels between knockdown mouse collecting duct cells and human ARPKD kidneys might be due to either increased ATMIN levels in ARPKD kidneys, modulation of which significantly affects non-canonical Wnt/PCP signalling or differences in the transcriptional regulatory mechanisms of Fibrocystin between mouse and human. This evidence concerns the gene WNT5A and autosomal recessive polycystic kidney disease.