ABCC8 and diabetes mellitus: We did not identify any rare homozygous variant in any known monogenic diabetes gene, but we identified a rare heterozygous variant in the ABCC8 gene, encoding sulphonylurea receptor 1 (SUR1, Table 1), which is a component of the ATP-sensitive potassium (KATP) channels that plays a key role in the regulation of insulin secretion by pancreatic β–cells.