Abstract
Alpha-1 antitrypsin deficiency (AATD) is a rare genetic condition classically associated with pulmonary emphysema and liver disease. However, the potential link between AATD and other respiratory diseases, particularly bronchial asthma, remains poorly understood and highly debated. This narrative review explores the current evidence regarding the epidemiological, clinical, and pathophysiological relationship between AATD and asthma. Data from prevalence studies show marked variability in the frequency of AATD-associated alleles among asthma patients, ranging from 2.9% to 25.4%, suggesting either a true association or selection biases. Conversely, asthma prevalence among AATD patients also varies widely, from 1.4% to 44.6%, with higher frequencies observed in countries with long-standing national registries. However, methodological inconsistencies and a lack of standardized diagnostic criteria limit the interpretation of these findings. Current evidence is insufficient to support a direct causal role for AATD mutations in asthma development, and no clear impact of AATD on asthma severity or prognosis has been established. Furthermore, there is no conclusive evidence that augmentation therapy is beneficial in asthma patients carrying AATD mutations. Despite these uncertainties, screening for AATD in selected asthma populations-especially those with severe or atypical phenotypes-may be warranted, as recommended by major respiratory societies. Future research should focus on large, well-powered, prospective studies that evaluate the potential pathophysiological interactions between AATD and specific asthma endotypes, particularly T2-low asthma. These efforts may help clarify the relevance of AATD mutations in asthma pathogenesis and identify potential therapeutic targets.