INS and Wolcott-Rallison syndrome: Patients unable to produce any insulin both prenatally and postnatally due to pancreatic agenesis or biallelic mutations in GCK or INS show lower birthweights, usually below −3 SDS for gestational age [64,65,66], compared to patients with heterozygous INS mutations or Wolcott-Rallison syndrome where birthweight, although typically low, is usually above −2 SDS for gestational age [25,44].