Abstract

Introduction: Alpha-1-antitrypsin deficiency (AATD) is a rare hereditary condition, which is characterized by low alpha-1 antitrypsin (AAT) serum levels. While the association between AATD and COPD/emphysema is indisputed, the association to bronchiectasis and asthma is a matter of debate.

Aims and Objectives: We compared the distribution of AAT genotypes between patients with COPD/emphysema, bronchiectasis and asthma.

Methods: Between 2003 and 2019, 27,223 testing kits (AlphaKit©) were analyzed in the German AAT laboratory, University of Marburg. The diagnosis of AATD was made through a measurement of AAT serum levels, followed by genotyping, phenotyping or whole gene sequencing depending on availability and/or the need for more detailed interpretation of the AAT results. Respiratory symptoms were additionally recorded on the kit.

Results: The distribution of the wild type (Pi*MM) was roughly comparable between the three groups. A higher percentage of COPD/emphysema and bronchiectasis patients exhibited the Pi*ZZ genotype as compared to asthma patients. In patients with bronchiectasis only, the distribution of alleles was as follows: M/M (59.4%), M/S (4%), M/Z (19.5%), S/S (0.8%), S/Z (2.8%), Z/Z (7.2%).

Figure 1: Distribution of AAT alleles among patients with COPD/emphysema, bronchiectasis and asthma

Conclusions: Not only patients with COPD/emphysema, but also patients with bronchiectasis (and asthma) should be screened for AATD.