PKD2 and polycystic kidney disease: Comparison of protein prediction models of the canonical (ENST00000369701.8) and novel isoform (Tx1) showed the addition of an unstructured loop with a partial alpha helix within the second polycystic kidney disease (PKD2) domain (Additional file 2: Fig. S18A–D), though the prediction confidence was low, so the structural impact on the PKD2 domain remains uncertain [53].