Hereditary factor X deficiency

Hereditary factor X (FXX) deficiency was first discovered by Hougie in a male patient named Stuart. Therefore, FXX is also known as "Stuart factor". Telfer also found similar performance in a female patient (Prower). When the two plasmas were found to be incapable of correcting partial prothrombin time (PTT) for prolonged periods, it was suggested to name this factor "Stuart-Prower factor" and later named "FXX".