HNF1A deficiency impairs β-cell fate, granule maturation and function

Mutations in HNF1A cause Maturity Onset Diabetes of the Young type 3, the second most frequent form of diabetes caused by single gene mutation. We generated human pancreatic stem cell-derived endocrine cells with mutations in HNF1A and show that HNF1A deficiency impairs scβ-cell fate, insulin granule maturation and the secretion of insulin in a glucose responsive manner. Single-cell RNA sequencing reveals that HNF1A orchestrates a network of genes involved in glucose metabolism, zinc transport, calcium ion binding and hormone exocytosis. Furthermore, in both patients and stem cell-derived β-cells, HNF1A deficiency altered the stoichiometry of secreted c-peptide to insulin. Sulfonylurea, used in the treatment of these patients, restored both insulin secretion and stoichiometry. Significantly, uncoupling of c-peptide and insulin secretion as described here questions the common practice in using c-peptide as a proxy to evaluate β-cell function. We also demonstrate that correction of the HNF1A locus restores function, providing a path to cell therapy.