Neonatal onset of congenital factor X deficiency: a description of two novel mutations with 6-year follow-up

Molecular basis of rare congenital bleeding disorders

Rare bleeding disorders (RBDs), including factor (F) I, FII, FV, FVII, combined FV and FVIII (CF5F8), FXI, FXIII and vitamin-K dependent coagulation factors (VKCF) deficiencies, are a heterogeneous group of hemorrhagic disorder with a variable bleeding tendency. RBDs are due to mutation in underlying coagulation factors genes, except for CF5F8 and VKCF deficiencies. FVII deficiency is the most common RBD with >330 variants in the F7 gene, while only 63 variants have been identified in the F2 gene. Most detected variants in the affected genes are missense (>50% of all RBDs), while large deletions are the rarest, having been reported in FVII, FX, FXI and FXIII deficiencies. Most were located in the catalytic and activated domains of FXI, FX, FXIII and prothrombin deficiencies. Understanding the proper molecular basis of RBDs not only can help achieve a timely and cost-effective diagnosis, but also can help to phenotype properties of the disorders.

Occurrence and management of severe bleeding episodes in patients with hereditary factor X deficiency

Vitamin K-dependent factor X (FX) plays an important role in thrombin formation, and a deficiency in FX can cause impaired coagulation, the severity of which is usually correlated with the degree of deficiency. Due to the critical role that FX plays in the coagulation cascade, FX deficiency is associated with a higher risk of bleeding than deficiencies in other coagulation factors. Patients with the hereditary autosomal-recessive homozygous form of FX deficiency, which occurs in approximately 1:1,000,000 individuals worldwide, are often diagnosed when they present with spontaneous life-threatening haemorrhage (most often intracranial haemorrhage) during the first month of life. In addition to central nervous system bleeds, other severe bleeding types experienced by such patients may include umbilical cord bleeding, gastrointestinal or pulmonary haemorrhage, intramuscular haematomas and/or haemarthrosis. Delayed treatment or inadequate replacement of FX may result in developmental delays, musculoskeletal disabilities or death. The high risk of recurrent severe bleeding necessitates prophylactic replacement therapy for many individuals with severe FX deficiency. Available products for replacement therapy include plasma-derived FX concentrate and prothrombin complex concentrates. Fresh-frozen plasma may be used when concentrates are not available but is a less efficient means of FX replacement. This article reviews the literature on severe bleeding in individuals with hereditary FX deficiency and discusses current treatment options.

Intracranial Hemorrhage as the First Manifestation of Severe Congenital Factor X Deficiency in a 20-Month-Old Male: Case Report and Review of the Literature

Factor X deficiency (FXD) is a rare bleeding disorder, which can result in severe bleeding symptoms such as intracranial hemorrhage (ICH). The most common bleeding symptoms are epistaxis and gum bleeding. ICH is reported in 9-26% of all patients with FXD, mostly during the first month of life. Here, we present a rare case of a male presenting with ICH at the age of 20 months as the first manifestation of FXD. Secondary prophylaxis with factor X substitution once weekly prevented further bleeding.