Coagulation profiles and bleeding tendency in 12 patients with factor X deficiency: first report of a homozygous p.Gln249Pro mutation

OBJECTIVE: To analyze the coagulation function and bleeding tendency in 12 patients with Factor X (FX) deficiency. METHODS: Activated partial thromboplastin time (APTT), prothrombin time (PT), and FX activity (FX:C) were measured. F10 gene mutations were identified via Sanger sequencing. Clinical data and bleeding tendency were assessed using the ISTH-BAT score. RESULTS: Among the 12 patients, 10 had hereditary FX deficiency and 2 had acquired deficiency. Four patients with FX:C of 40-50% and heterozygous c.746A>C (p.Gln249Pro) mutations had no bleeding tendency. Five patients with F.X:C of 30-50% and heterozygous mutations (c.452G>A, c.871C>T, or c.1252G>A) showed mild bleeding. One patient with severe bleeding (FX:C <1.0%) had a homozygous c.746A>C (p.Gln249Pro) mutation - representing the first global report of this genotype. Two acquired cases had FX:C of 9% and 3%, with mild and moderate-severe bleeding, respectively. CONCLUSION: Severe bleeding in FX deficiency is associated with FX:C <5%, while milder deficiencies often present minimal symptoms. The novel homozygous p.Gln249Pro mutation causes a severe phenotype, highlighting the importance of genetic diagnosis.