Associations between mutations in the INS, INSR, IPF1, KCNJ11, ABCC8 and HNF1B genes reducing fetal insulin secretion and markedly reducing birth weight in monogenic diabetes provide support for a genetic role in the modulation of birth weight, although this cannot be extrapolated to the general population due to the rarity of these mutations [5], [8]–[10]. This evidence concerns the gene INS and diabetes mellitus.