After how much time does the child suffering from thalassemia major show symptoms of disease after birth?

6-8 months for beta: Alpha thalassemia major is generally fatal before birth, with just rare cases born alive. Beta thalassemia major babies look normal at birth because fetal hemoglobin doesn't need beta globulin. As fetal hemoglobin goes away and adult hemoglobin starts being made, the baby will feel the effects of his lack of beta globulin. Symptoms start after the first 6-8 months of life.

Thalassemia major: Thalassimia major (with two beta genes positive) may have minor or no expressions at birth, but anemia should be carefully and immediately watched, as deficiencies in hemoglobin may result in bone deformaties, and more profound anemia.