[15] Crystal structures have been solved for the dimerization domain, which forms a four-helix bundle where two α helices are separated by a turn; the DNA-binding motif, which forms a helix-turn-helix structure; and the POU-homeodomain, which is composed of three α helices, contained in the motif.

[15] HNF-1α is a transcription factor expressed in organs of endoderm origin, including liver, kidneys, pancreas, intestines, stomach, spleen, thymus, testis, and keratinocytes and melanocytes in human skin.

[20][21] HNF-1α could promote the transcription of several proteins involved in the management of type II diabetes including dipeptidyl peptidase-IV (DPP-IV/CD26).

[22][23] HNF-1α is also involved in various metabolic pathways of other organs, such as being a transcriptional regulator of bile acid transporters in the intestine and kidneys.

[24] HNF-1α is involved in the promotion of hepatic organic cation transporters, which uptake certain classes of pharmaceuticals; hence, the loss of its function can lead to drug metabolism problems.

[10] Likewise, patients with diabetes caused by mutations in the HNF1A gene have been described as sensitive to the hypoglycemic effects of sulphonylureas.

This pharmacogenetic effect is consistent with models of HNF-1α deficiency, and the genetic basis of hyperglycemia may have implications for patient management.