Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Alpha-1 antitrypsin deficiency ?
    ### Response:
    Alpha-1 antitrypsin deficiency (AATD) is a disorder that causes a deficiency or absence of the alpha-1 antitrypsin (AAT) protein in the blood. AAT is made in the liver and sent through the bloodstream to the lungs, to protect the lungs from damage. Having low levels of ATT (or no ATT) can allow the lungs to become damaged, making breathing hard.
    