Figure 1.

F9 gene analysis and determination of FIX Shanghai clotting function. (A). A F9 gene variant c.1151G>A was identified in the patient, which predicted a missense mutation in factor IX (FIX) p.Arg338Gln (p.R338Q). (B) The mutation was inherited from the patient’s mother. (C) Subjected to electrophoresis, the FIX mutant p.R338Q expressed in HEK293 cells migrated in the same fashion as wild-type (wt) FIX on a sodium dodecylsulfate polyacrylamide gel. (D) Both recombinant FIX p.R338Q and FIX from the patient’s plasma showed more potent FIX activity, as represented by the increased ratio between FIX:C and FIX:Ag.