HNF1A-AS1 and Hyperglycemia: Remarkably, compound heterozygous Hnf1a+/−;Haster+/− young mice developed severe fasting and fed hyperglycaemia with hypoinsulinaemia, but otherwise did not exhibit extra-pancreatic manifestations observed in homozygous Hnf1a-mutant mice24,26 (Fig. 5a).