PKD2L1 and kidney disorder: The TRPP family is structurally divided into two groups, polycystic kidney disease 1-like proteins (PKD1-like, TRPP1-like), including PKD1, PKDL1-3 and PKDREJ, and polycystic kidney disease 2-like (PKD2-like, TRPP2-like) proteins, including PKD2, PKD2L1 and PKD2L2, which have a completely different protein architecture.