Although MODY accounts for only 1–5% of all diabetes cases it has significant implications [2]. There are now at least 14 different known MODY subtypes corresponding to pathogenic variants in the same number of genes (HNF4α, GCK, HNF1α, PDX1, HNF1B, NEURO1, KLF11, CEL, PAX4, INS, BLK, ABCC8, KCNJ11 and APPL1). The gene discussed is HNF1B; the disease is MODY.