Could one prevent beta thalassemia disease?

Yes. Beta thalassemia disease is prevented if beta thal carriers do not have children with one another (if they have children together, some children will be normal, some carriers, and some have disease). The other, less desirable way, is to test fetuses during pregnancy and abort the fetuses who have beta thal major.
Prenatal counseling. It can prevented if there is a penal al checkup for both parties.