A full evaluation for thrombophilia is reasonable in all children with stroke and may include protein C and protein S deficiency, antithrombin III, heparin cofactor II, plasminogen, vonWillebrand antigen, factor VIII, factor XII, factor V Leiden, activated protein C resistance, prothrombin 20210 gene, serum homocysteine, MTHFR, lipoprotein (a), and antiphospholipid antibodies. Here, PROS1 is linked to hyperinsulinemic hypoglycemia, familial, 4.