This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Integrated QBank, Subject name: Unknown
A 40-year-old male presented with symptoms of anemia along with weight loss, night sweats, and low-grade fever.On examination, splenomegaly, petechiae, ecchymosis, lymphadenopathy was noted along with some features of poal hypeension.Lab findings revealed anemia, leukocytosis and thrombocytosis. Bone marrow aspiration reveals a dry tap. Bone marrow biopsy was taken and subjected to reticulin staining.. All of the following genes can be mutated in the above condition except: - 
Select and explain. 
A. JAK2, B. CALR, C. MPL, D. ACTN3
D: ACTN3
Answer: D: ACTN3 
Explanation: This is a case of primary myelofibrosis. Primary myelofibrosis. Peripheral smear shows teardrop red blood cells (RBCs) and a leukoerythroblastic picture with nucleated RBC precursors and immature myeloid cells. Bone marrow biopsy from a patient with primary myelofibrosis shows extensive fibrosis which is confirmed by reticulin staining. Mutations in the JAK2, MPL, CALR, and TET2 genes are associated with most cases of primary myelofibrosis.