Vitamin K level explains the discrepancy in bleeding tendencies in patients with the same mutation. (A) Different bleeding tendencies were observed in hemophilia B patients with the same mutation in the database. (B) The SCSR levels of the mutations are dependent on the vitamin K concentration. SCSR levels of the mutants were corrected by Metridia luciferase and normalized to the SCSR level of wild-type (WT) FIX-PC at 50 μM vitamin K. The error bars indicate the standard deviation from 3 biological replicates.