Protein S deficiency—coagulation method: STA-Staclot Protein S set by Stago (Asnières-sur-Seine, France); if activity is low, free PS and total PS antigens are measured through the ELISA method: Asserachrom Free Protein S and Asserachrom Total Protein S sets by Stago (Asnières-sur-Seine, France). The gene discussed is PROS1; the disease is hyperinsulinemic hypoglycemia, familial, 4.