Clinical and laboratory characteristics of patients with congenital factor XII deficiency in the Russian population

Introduction. The blood coagulation factor XII (FXII) is involved in opposing processes of hemostasis: contact activation of the intrinsic pathway of blood coagulation and fibrinolysis. What might the clinical picture of FXII deficiency present with: bleeding, thromboses or be asymptomatic? The issue remains debatable. Aim: To present the clinical and laboratory characteristics of patients with congenital FXII deficiency in the Russian population. Materials and methods . A retrospective study included 29 of 212 patients with FXII deficiency who underwent genetic analysis, confirming the hereditary nature of the disease. Results. The mean APTT in the study group was 187 seconds (control 29–38 sec.). The mean FXII activity was 20%. The most common mutation of F12 in the Russian population was the nucleotide substitution c.1681 –1 G>A. The reasons for contacting a hematologist and conducting diagnostics of the disease were: preoperative examination in 9 (31%) patients; abnormalities in the coagulogram during examination prior to pregnancy planning or during examination for a chronic disease in 8 (28%) patients; bleeding — in 7 (24%) patients; abnormalities in the coagulogram during screening in pregnancy in 2 (7%); family examination in 2 (7%) patients. In 21 (72%) of 29 patients, the clinical picture was represented by hemorrhagic manifestations. Thrombotic events were noted in 2 (7%) of 29 patients. Among 16 (80%) women with a history of pregnancy, miscarriages occurred in 6 (38%). Conclusion. The diagnosis of hereditary FXII deficiency is most often established during preoperative examination. However, 24% of patients consulted a hematologist with complaints of hemorrhagic manifestations, mostly mild or moderate. Surgical bleeding was noted in 21% of patients. The obstetric history of more than a third of women was complicated by miscarriages. In patients with hereditary FXII deficiency, it is necessary to be wary of mild spontaneous bleeding, surgical bleeding, miscarriage and, to a lesser extent, thromboses.