INVS and autosomal recessive polycystic kidney disease: This implies that NPHP2 transcription is unlikely to have significant involvement in ARPKD and that the observed reduction in total β-catenin levels in ARPKD is a consequence of increased non-canonical Wnt/PCP signalling, as dys-regulation of the non-canonical Wnt/PCP pathway can impact on canonical Wnt signalling.