Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Thalassemia ?
    ### Response:
    What causes thalassemia? There are two main types of thalassemia, alpha thalassemia and beta thalassemia, which each affect a different part of hemoglobin (the protein in red blood cells that carries oxygen). Hemoglobin is made up of two different components (subunits): beta globin and alpha globin.
    