Factor XI deficiency: a description of 34 cases and literature review.

Factor XI (FXI) deficiency is a rare bleeding disorder, resulting in a wide range of bleeding manifestations, from asymptomatic bleeding to injury-related bleeding. First in this review, we give an overview of the basic pathophysiology, clinical manifestations, and management of FXI deficiency. Finally, we describe 34 members of 16 FXI-deficient kindreds from south Italy, diagnosed and followed at the Haemophilia, Haemostasis and Thrombosis Centre of Pugliese-Ciaccio Hospital, Catanzaro, during the past 20 years. In our patients, bleeding tendency did not appear to be correlated with FXI levels. Furthermore, we describe 24 pregnancies in 11 patients with FXI deficiency. In all the pregnancies, no bleeding manifestations were reported.