Nonsynonymous mutations in three anticoagulant genes in Japanese patients with adverse pregnancy outcomes

Abstract

Background: Hereditary thrombophilias may associate with uteroplacental thrombosis leading to adverse pregnancy outcomes. The present study was conducted to reveal the frequency of the low-frequency thrombophilic protein S K196E mutation, as well as the frequency of very rare nonsynonymous mutations in protein S, protein C, and antithrombin genes, in patients with adverse pregnancy outcomes.

Patients and methods: We enrolled 330 Japanese patients with adverse pregnancy outcomes and divided them into 233 patients with two or more miscarriages and 114 patients with fetal growth restriction (FGR) and/or intrauterine fetal death (IUFD); 17 patients belonged to both groups. We sequenced the entire coding regions of three anticoagulant genes in all 330 patients.

Results: We found that protein S K196E mutation was identified in 4 out of 233 patients with recurrent miscarriage and in 2 out of 114 patients with FGR and/or IUFD. The frequencies of this mutation in these patient groups were not different from that in a Japanese general population. Very rare nonsynonymous mutations were identified in 3.3% (11 out of 330) of patients with adverse pregnancy outcomes.

Conclusions: Although the low-frequency protein S K196E mutation can increase the risk for venous thromboembolism, it did not increase the risk for adverse pregnancy outcomes even in Japanese.

Keywords: Fetal death; Fetal growth restriction; Miscarriage; Protein S; Thrombophilia.