Hereditary Severe Insulin-resistance Syndrome and Acanthosis Nigricans Caused by Novel Mutations in the INSR Gene.

Most cases of hereditary severe insulin-resistance syndrome (H-SIRS) are linked to mutations in the insulin receptor (INSR) gene. Patients with H-SIRS typically manifest symptoms of hyperinsulinemia, insulin resistance, and diabetes mellitus. Other symptoms include impaired glucose regulation, hyperandrogenism, and the presence of acanthosis nigricans (AN). In this report, we present two cases of H-SIRS in female children exhibiting various symptoms, including hyperinsulinemia, fasting hypoglycemia, postprandial hyperglycemia, overweight, fatty liver, hyperandrogenism, and varying degrees of AN. One patient also presented with mental retardation. Gene sequencing identified specific mutations in the INSR gene for both patients: c.2663A > G (p.Tyr888Cys) in Patient 1 and c.38_61del (p.Pro13_Ala20del) in Patient 2. These mutations both have the potential to disrupt the interaction between the insulin receptor, INSR, and insulin, leading to abnormal insulin signaling, insulin resistance, and various clinical manifestations.