What are the symptoms of Beta thalassemia?

"Some children with mild thalassemia have no symptoms at all. In children who do, symptoms of thalassemia can range . The one gene defect, beta thalassemia trait (minor), is asymptomatic and results in microcytosis and mild anemia. If the synthesis from both genes is severely reduced or absent, the person has beta thalassemia major, also known as Cooley anemia. Persons with beta thalassemia major are almost never symptomatic at birth because of the presence of HbF, but symptoms begin to develop by six months of age. If the synthesis of beta chains is less severely reduced, the person has beta thalassemia intermedia. These persons experience symptoms that are less severe and do not require lifelong transfusions. "