PROS1 and hyperinsulinemic hypoglycemia, familial, 4: Protein C deficiency, protein S deficiency, Factor V mutation, prothrombotic polymorphisms, Factor II G2021A, and the homozygous TT genotype of the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism were found to be associated with increased risk of arterial thrombosis in neonates.