Congenital Factor X-Riyadh (Stuart-Prower) Deficiency With Isolated Prothrombin Time Prolongation: A Case Report.

Factor X (FX) deficiency is an extremely rare autosomal recessive inherited coagulation defect. We report a case of congenital Factor X-Riyadh deficiency discovered during a routine workup before a dental procedure. During routine work-up for dental surgery, prothrombin time (PT) and the international normalized ratio (INR) were prolonged. The prothrombin time (PT) was found to be 78.4 (normal 11-14 seconds) with an international normalized ratio (INR) of 7.83; the activated partial thromboplastin time (APTT) was 30.7 (normal 25-42 seconds). Specific coagulation factor assays confirmed an FX deficiency (<10 % of normal activity) and a mild factor VII deficiency 37% (normal 48%-124%). Molecular genetic analysis of the whole exome sequence (WES) confirmed the diagnosis of FX deficiency (homozygous pathogenic variant c. 271G>A p {Glu91Lys} chr13:113793685). The patient is currently on regular follow-up and is advised to take oral antifibrinolytic medications for any superficial or mucosal bleeding.