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
Pancytopenia with a cellular marrow is seen in all except: 
Select and explain. 
A. PNH, B. Megaloblastic anemia, C. Myelodysplastic syndrome, D. Dyskeratosis congenital
D: Dyskeratosis congenital
Answer: D: Dyskeratosis congenital 
Explanation: Answer is D (Dyskeratosis congenita) Dyskeratosis congenita is associated with Pancytopenia and a hypocellular marrow.