Rare bleeding disorders: Real-world data from a Spanish tertiary hospital

Introduction: Due to their low prevalence, rare bleeding disorders (RBDs) remain poorly characterized. Aim: To gain insight of RBDs through our clinical practice. Methods: Retrospective study of the medical records of RBD patients followed up at the Central University Hospital of Asturias between January 2019 and December 2022. Results: A total of 149 patients were included. Factor (F) VII (44 %) and FXI (40 %) deficiencies were the most common diagnosed coagulopathies. Most of the patients were asymptomatic (60.4 %) and the most frequent type of bleeding were mucocutaneous and after surgery. All replacement treatments were administered on demand and no patient was on a prophylaxis regimen. Currently available products were safe; allergic reactions after administration of plasma were the most frequent complication. Genetic analysis, carried out on 55 patients (37 %), showed that the most frequent mutations in RBDs are of missense type (71.9 %). We identified 11 different novel genetic alterations in affected genes. The c.802C > T (p.Arg268Cys) variant, previously described, was identified in 71 % (15 of 21) of the patients with FXI deficiency genotyped and none were related (probable founder effect). Conclusion: Our study on an unusual large single center cohort of RBD patients portrays location-dependent distinct genetic drives and clinical practice particularities.