Individuals born prematurely or with low-birth weight are at increased risk for developing schizophrenia.73 Assuming a high prevalence of hereditary protein S deficiency or inherited conditions reducing tPA activity among mothers of schizophrenia patients, one would expect in this group an increased prevalence of pregnancy complications related to abnormal placentation. Here, PROS1 is linked to hyperinsulinemic hypoglycemia, familial, 4.