Abnormalities in the insulin receptor gene (INSR) can cause genetic insulin resistance, including DS, Rabson–Mendenhall syndrome (RMS), and type A insulin resistance, which are identified by the severity of the receptor function defect and unique physical characteristics of the affected individual.[1] DS, with an incidence of approximately 1 in 4 million births, is the most severe syndrome.[2] It is characterized by intrauterine and postnatal growth retardation, coarse facial features, severe insulin resistance, and fasting hypoglycemia. The gene discussed is INSR; the disease is Insulin resistance.