To explore these possibilities and obtain a more comprehensive view of HNF1B function in organ development and disease in the context of the whole animal, we generated a novel RCAD mouse model by introducing a previously identified human hotspot mutation at the intron-2 splice donor site (<IVS2nt+1G>T) (Bingham et al., 2003; Harries et al., 2004). The gene discussed is HNF1B; the disease is renal cysts and diabetes syndrome.