Below is an instruction from Human. Write a response.
    ### Instruction:
    How to diagnose Alpha-1 antitrypsin deficiency ?
    ### Response:
    How is alpha-1 antitrypsin deficiency diagnosed? Alpha-1 antitrypsin deficiency (AATD) may first be suspected in people with evidence of liver disease at any age, or lung disease (such as emphysema), especially when there is no obvious cause or it is diagnosed at a younger age.
    