At 27 weeks of gestation, a 23-year-old white gravida 2 para 0, with a type 1 diabetes (first diagnosis 8 years ago, HbA1c periconceptual 6%) on intensified insulin regimen was transferred to our hospital from a peripheral clinic because of persisting hematemesis, presenting in a desolate condition. The gene discussed is INS; the disease is type 1 diabetes mellitus.