Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) alpha thalassemia ?
    ### Response:
    Alpha thalassemia is a blood disorder that reduces the production of hemoglobin. Hemoglobin is the protein in red blood cells that carries oxygen to cells throughout the body.  In people with the characteristic features of alpha thalassemia, a reduction in the amount of hemoglobin prevents enough oxygen from reaching the body's tissues.
    