HNF1B and type 2 diabetes mellitus: For example, mutations of the nuclear protein vhnf1 (tcf2) are associated with maturity-onset diabetes of the young, type V (MODY5). Vhnf1 mutant zebrafish embryos displayed developmental defects in the pancreas and the liver, along with the formation of kidney cysts, which are also found in MODY5 patients [65, 66].