This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Haematology, Subject name: Pathology
Leiden mutation is associated with? 
Select and explain. 
A. Factor IV, B. Factor V, C. Factor VIII, D. Factor IX
B: Factor V
Answer: B: Factor V 
Explanation: Leiden mutation is associated with factor 5.This is also a autosomal dominant disorder in which mutation lies in the replacement of arginine by glycine at position 506.Most common cause of thrombophilia. Reference :Harsh Mohan textbook of pathology 7th edition.Pg no.102