In this direction, the diagnosis of thrombophilia is realized using genetic tests (factor V Leiden, MTHFR, factor VII, prothrombin, SERPING 1 gene mutations) or biological laboratory testing (protein C, protein S or antithrombin deficiency, antiphospholipid antibodies), having a clear role in predicting adverse pregnancy outcomes, especially fetal growth restriction, such as factor V Leiden mutation, MTHFR C667T mutation, protein S deficiency, antithrombin deficiency, factor VII polymorphism, antiphospholipid antibodies and the coexistence of multiple types of thrombophilia. The gene discussed is MTHFR; the disease is hyperinsulinemic hypoglycemia, familial, 4.