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
Thalassaemia major manifests in 
Select and explain. 
A. Childhood, B. Pubey, C. Adolescence, D. Middle age
A: Childhood
Answer: A: Childhood 
Explanation: Beta thalassemia major manifests 6 to 9 months after bih as Hb synthesis switches from HbF to HbA. Beta thalassemia is caused by the mutation that diminishes the synthesis of beta globin chain seen in HbA. The red cells may completely lack HbA or contain small amounts. Reference: Robbins and Cotran Pathologic basis of disease.South Asia Edition,-9 volume 1.page no. 638-639