At the age of 3 years and 2 months, the boy was hospitalised in the department of paediatric endocrinology due to hypoglycaemia with transient hyperinsulinaemia (the outpatient laboratory tests showed glycaemia at 54 mg/dL with insulin at 75.1 μIU/mL, and fasting glycaemia at 49 mg/dL [normal range: 60–99 mg/dL] with insulin at 6.8 μIU/mL [normal range: <24.9 μIU/mL]). The gene discussed is INS; the disease is Hypoglycemia.