This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
[{'content': 'A 13-year old girl with Menorrhagia having Von Willebrands disease will show : \nSelect and explain. \nA. Isolated prolonged PT with a normal PTT, B. Prolongation of both PT and PTT, C. Prolongation of thrombin time, D. Isolated prolonged PTT with a normal PT', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Von Willebrand\'s factor acts as a plasma carrier of factor VIII and circulates in the blood as factor VIII-VWF complex. Its deficiency therefore impairs the intrinsic pathway of coagulation and prolongs the GPTT as the intrinsic pathway of coagulation. Ref:Kligman, Behrman, Jenson, Stanton (2008), Chapter 477, "VON WILLEBRAND DISEASE", In the book, "Nelson\'s Textbook of Pediatrics", Volume 2, 18th Edition, New Delhi, Page 2073', 'role': 'assistant'}]