PLE-5678

PLE-5678

An otherwise healthy 16-year-old girl comes to the physician because of a 4-year history of heavy bleeding with menses. She has a history of excessive bleeding after a dental extraction but has never had spontaneous bleeding. Her father has a history of frequent nosebleeds and postoperative bleeding. Her mother, sisters, and brother have no history of bleeding disorders. Examination of the patient shows no abnormalities except for pallor. Laboratory studies show Hb 8, Hct 25%, Reticulocyte count 2%, platelet count 200000, bleeding time 12 min, INR 1, APTT 60 seconds. Pelvic ultrasonography shows no abnormalities. Which of the following is the most likely mechanism of this patient’s excessive bleeding?