Although mutations in the gene HNF-1beta (or TCF2) were originally discovered in patients with mature-onset diabetes of the young (MODY), patients with these mutations more commonly present with a variable renal phenotype. Interestingly, a study by Egdhill et. al. (NDT 2008) looked at a cohort of 160 patients with unexplained renal disease and 38 (24%) had mutations in NHF-1beta! Most mutations arise de novo and hence there may not necessarily be a family history. The disease is inherited in an autosomal dominant fashion and may involve the formation of cystic kidneys, accounting for its being confused occasionally with ADPKD. HNF-1beta is a transcription factor implicated in kidney development, and thus patients with these mutations are thought to have a problem with the congenital development of the kidney.