A series of Polish patients with congenital fibrinogen disorders: 2 new mutations in fibrinogen gamma chain, Fibrinogen Kostrzyn and Fibrinogen Łódź II

RESEARCH LETTER A series of Polish patients with congenital fibrinogen disorders 1 often detected incidentally, for example, before surgery. 4,7Less than 50 cases of Polish patients with congenital fibrinogen disorders and identified causal mutations have been reported until now, 8 -10 including the largest cohort of 27 unrelated patients. 11Here, we present a series of 12 newly diagnosed, consecutive Polish patients with their clinical and genetic characterization, and describe 2 previously unreported mutations in the FGG gene. Patients and methodsWe evaluated 12 unrelated patients with a fibrinogen concentration (von Clauss method) below 1.8 g/l in at least 2 separate measurements, who were referred to the Center for Coagulation Disorders at the John Paul II Hospital, Kraków, Poland.The patients were enrolled between June 2019 and March 2021.We collected data on the clinical manifestations at enrolment and during follow -up.Major bleeding and clinically relevant nonmajor bleeding (CRNMB) were defined according to the International Society on Thrombosis and Haemostasis criteria. 12Minor bleeding was defined as any overt bleeding event that did not fulfill the criteria of major bleeding or CRNMB.An unprovoked episode of venous thromboembolism (VTE) was defined as previously described. 13 The diagnosis of deep vein thrombosis (DVT) was established on the basis of a positive