<prompt> The coagulation profile in a 13 year old girl with Menorrhagia having von Willebrands disease is:Isolated prolonged aPTT with a normal PTIsolated prolonged PT with a normal aPTTProlongation of both PT and aPTTProlongation of thrombin time  <response>: - Von Willebrand factor acts as a plasma carrier of factor VIII and circulates in blood as factor VIII-VWF complex. - Thus, VWF deficiency impairs intrinsic pathway of coagulation prolongs aPTT - Extrinsic pathway of coagulation remains unimpaired, PT is not altered. 