Factor XI deficiency: About 20 cases and literature review

Introduction: Factor XI deficiency is a rare coagulation disorder with variable bleeding manifestations. Objectives: To evaluate the correlation between the degree of factorXI deficiency and the clinical expression of the disease. Methods: Retrospective study, spanning 10 years from January 1, 2010 to December 31, 2019, concerning patients followed at the Hemophilia Center at Aziza Othmana Hospital in Tunis. The data were collected from the medical records. The determination of PT, APTT, fibrinogen level and coagulation factors are performed by coagulometric technique on STA® compact / ACL TOP®. FactorXI deficiency was confirmed on two different samples. Statistical analysis of the clinical-biological correlation was performed using the chi-square test. The significance level was 0.05. Results: Twenty patients were collected. The mean age of discovery was 25 years with a sex ratio (M/F) =0.33. The circumstances of discovery were incidental in 14 patients. A family history of bleeding was reported in 30% of cases. Eight patients underwent surgery, six of whom had a simple postoperative course. The APTT was prolonged and isolated in 75% of cases. The hemostasis test was normal in 5 cases. The average FactorXI level was 24%. The tendency to bleed did not seem to be correlated with FactorXI levels. Conclusion: Prospective multicenter studies including molecular study would be necessary to better elucidate this rare disorder.