For example, neonatal onset (directed neonatal diabetes gene panel testing); retrospective mild fasting hyperglycaemia (characteristic of GCK); high HDL (HNF1A); neonatal macrosomia (HNF4A) and syndromic features present in patients with either HNF1B or mitochondrial forms (MIDD) (5). Here, HNF1B is linked to diabetes mellitus.