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: Medicine
Splenectomy is not useful as a mode of treatment in which of the following conditions? 
Select and explain. 
A. Porphyria, B. Thalassemia, C. Herediatary spherocytosis, D. Sickle cell disease with large spleen
A: Porphyria
Answer: A: Porphyria 
Explanation: Splenectomy is the modality of treatment for hereditary spherocytosis, thalassemia & sickle cell anemia. Splenectomy is of little benefit in the treatment of porphyria. Porphyrias are metabolic disorders, resulting from deficiency of enzymes in the heme biosynthetic pathway. These enzyme deficiencies are inherited as autosomal dominant, autosomal recessive, or X-linked traits, with the exception of porphyria cutanea tarda (PCT), which is usually sporadic. Ref: Harrisons Internal Medicine, 18th Edition, Chapter 358; Williams Hematology, 8th Edition, Chapter 57