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
Intrinsic causes of hemolytic anemia are all except- 
Select and explain. 
A. Hypersplenism, B. G6PD deficiency, C. Hereditary spherocytosis, D. Pyruvate kinase deficiency
A: Hypersplenism
Answer: A: Hypersplenism 
Explanation: Intrinsic causes of hemolytic anemias are due to defective RBCs which includes- Hereditary spherocytosis,Hereditary elliptocytosis, Hmp shunt enzyme deficiency(G6PD deficiency), glycolytic enzyme (pyruvate kinase )deficiency, thalassemia, sickle cell disease . While in hyper splenism RBCs are destroyed by sequestraion which is an extrinsic cause. Ref : Robbins pathologic basis of disease edition :9 pg 630 ; table 14-1