Molecular and clinical profile of rare bleeding disorders: A single-center retrospective study

Due to their low frequency, there is little information on the molecular pathologies of rare bleeding disorders (RBD). Therefore, this study aimed to analyze the molecular and clinical profiles of patients with RBD.

A retrospective single-center study was conducted among patients with factor (F) II, FVII, FX, and FXIII deficiencies between March 20, 2000, and June 31, 2023. Data on patient demographics, genetic analysis, and laboratory results were documented for all patients. The disease severity was classified according to the clotting factor activity (except FXIII) as follows: >5%: mild, 1-5%: moderate, and <1%: severe.

A total of 79 patients were enrolled in this study. Three of the cases had FII (3.7%), 40 had FVII (50.6%), 20 had FX (25.3%), and 16 had FXIII deficiency (20.2%). The median age of the patients at the time of diagnosis was six months for FII, 6.5 years for FVII, five months for FX, and 5.75 months for FXIII deficiencies, respectively. The major clinical manifestations were bruising, epistaxis, oral cavity bleeding, ecchymosis, and hemarthrosis. Consanguinity was present in 60 (76%) of patients. The majority of the patients had missense mutations. FVII mutations occurred primarily in exon 6, FX mutations affected mainly exons 2 and 7, and the majority of FXIII mutations occurred in exons 3 and 4.

The diagnosis of the causative mutations in patients with RBD provides an insight into the underlying molecular basis of these disorders and probably explains their variable clinical manifestations.