This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Pathology
Alpha-1 antitrypsin deficiency occurs in 
Select and explain. 
A. Emphysema, B. Bronchiectasis, C. Empyema, D. Bronchogenic carcinoma
A: Emphysema
Answer: A: Emphysema 
Explanation: Alpha-1 antitrypsin deficiency (A1AD or AATD) is a genetic disorder that may result in lung disease or liver disease. Onset of lung problems is typically between 20 and 50 years old. This may result in shoness of breath, wheezing, or an increased risk of lung infections Affected individuals often developemphysema, which is a lung disease caused by damage to the small air sacs in the lungs (alveoli). ... In rare cases, people with alpha-1 antitrypsin deficiency develop a skin condition called panniculitis, which ischaracterized by hardened skin with painful lumps or patches.