What deficiency leads to COPD without smoking?

Alpha-1 antitrypsin deficiency is a genetic condition that can lead to chronic obstructive pulmonary disease (COPD) independent of smoking. Alpha-1 antitrypsin (AAT) is a protein produced by the liver that protects the lungs from damage caused by enzymes released by white blood cells during inflammation. AAT deficiency can result in reduced levels of this protective protein, making the lungs more susceptible to damage and inflammation, leading to the development of COPD.

Individuals with this deficiency may experience lung problems earlier in life and may develop COPD even if they have never smoked. This is significant because most other causes of COPD, such as smoking and environmental pollutants, result in damage due to direct exposure to harmful substances. In contrast, AAT deficiency is an inherent condition that predisposes individuals to lung disease due to a lack of the necessary protective mechanisms.

In summary, the reason this answer is correct lies in the understanding of the role of alpha-1 antitrypsin in lung protection and the fact that its deficiency can manifest as COPD without the influence of smoking.