However, another study reported three cases with poor obstetric outcomes; one patient was homozygous for mutations in the methylene-tetrahydrofolate reductase gene C677T and suffered fetal demise at 30 gestational weeks, and the other two patients had a protein S deficiency and had second-trimester losses [25]. Here, PROS1 is linked to hyperinsulinemic hypoglycemia, familial, 4.