PO0046 - Distribution of Inherited Thrombophilia Disorder and Experiences of Extremely Low Level of Protein-C: A Single-Center Study

Background: Thrombophilia is a group of diseases in which blood clots well, and may occur due to congenital or acquired conditions. Inherited thrombophilia should be suspected when thrombosis occurs repeatedly or in unusual places or situations, and it is necessary to differentiate it from the secondary causes. Recently differentiation is becoming possible through the next-generation sequencing panel.

Aims: The purpose of this study was to compare the thrombosis according to the characteristics and level of inherited thrombophilia patients.

Methods: Inherited thrombophilia patients who were diagnosed or treated between the years 2005 and 2021 in Severance Hospital were enrolled in this study. They were classified according to diagnosis and first thrombosis event. In addition, among patients who had a recurrent pregnancy loss, cases with suspicion of inherited thrombophilia were analyzed.

Results: 65 patients with inherited thrombophilia disorder were diagnosed or treated. 27.7%(n=18) of them had protein-C deficiency, 53.8%(n=35) had protein-S deficiency, 15.4%(n=10) had an antithrombin-III deficiency, followed by factor V Leiden and prothrombin mutation. The most common symptoms are pain or swelling of low extremity(27.8%) for protein-C, and recurrent pregnancy loss (37.1%) for protein-S deficiency. Genetic studies were performed on 49.2%, and genetic variation was confirmed in 78.1%. Median concentrations were 35%, 30%, and 45% in protein-C deficiency, protein S deficiency, and antithrombin-III deficiency, respectively. And there were 5 patients with severe protein-C deficiency and 1 with antithrombin-III deficiency, they had more hospitalized conditions. Inherited thrombophilia patients with recurrent pregnancy loss were almost protein s deficiency (92.8%) and the concentrations were 36% (28-40%), and they were treated with LMWH and aspirin during pregnancy.

Conclusion(s): Patients with low levels experience thrombosis at younger ages, require early intervention. But the others did not know until adults and developed deep vein thrombosis or recurrent pregnancy loss. And patients with family history and genetic confirmation alone often didn’t require treatment.