HNF1A and type 2 diabetes mellitus: In addition to enrichment ofHNF motifs among genes more highly expressed in the ileum relative to the caecum and rectum, we identified increased expression ofHNF1A in the ileum.HNF1A is a key transcription factor in multiple metabolic processes across multiple cell types, with mutations inHNF1A causing maturity-onset diabetes of the young (MODY)56.