The Distribution of Alpha-1 Antitrypsin Genotypes Between Patients with COPD/Emphysema, Asthma and Bronchiectasis.

Purpose: Alpha-1-antitrypsin deficiency (AATD) is a rare hereditary condition characterized by low circulating levels of alpha-1antitrypsin (AAT). While the association between AATD and COPD/emphysema is undisputed, the association between AATD and asthma or bronchiectasis is still a matter of debate. Aims and Objectives: Our study aimed to investigate the distribution of AAT genotypes between patients with COPD/emphysema, asthma and bronchiectasis. To back up the diagnostic labels, we described symptoms associated with the diagnosis. Methods: Between September 2003 and March 2020, 29,465 testing kits (AlphaKit®) were analyzed in the AAT laboratory, University of Marburg, Germany. The diagnosis of AATD has been made based on the measurements of AAT serum levels, followed by genotyping, phenotyping or whole gene sequencing depending on the availability and/or the need for more detailed interpretation of the results. The respiratory symptoms were recorded as well. Results: Regarding the distribution of the wild type allele M and the most frequent mutations S (E264V) and Z (E342K), no significant differences could be found between COPD/emphysema [Pi*MM (58.24%); Pi*SZ (2.49%); Pi*ZZ (9.12%)] and bronchiectasis [Pi*MM (59.30%) Pi*SZ (2.81%); Pi*ZZ (7.02%)]. When COPD/emphysema and bronchiectasis were recorded in the same patient, the rate of Pi* ZZ (14.78%) mutations was even higher. Asthma patients exhibited significantly less deficient genotypes [Pi*MM (54.81%); Pi*SZ (2%); Pi*ZZ (2.77%)] than two other groups. Associated respiratory symptoms confirmed the diagnosis. Conclusion: COPD/emphysema and bronchiectasis, but not asthma patients, exhibit higher frequency of AATD genotypes. Our data suggest that AATD testing should be offered to patients with COPD/emphysema and bronchiectasis.

Diagnosing Alpha-1-Antitrypsin Deficiency Using A PCR/Luminescence-Based Technology.

Purpose: Alpha-1-antitrypsin deficiency (AATD) is a rare hereditary condition resulting from the mutations in the SERPINA1 (serine protease inhibitor) gene and is characterized by low circulating levels of the alpha-1 antitrypsin (AAT) protein. The traditional algorithm for laboratory testing of AATD involves the analysis of AAT concentrations (nephelometry), phenotyping (isoelectric focusing, IEF), and genotyping (polymerase chain reaction, PCR); in selected cases, full sequencing of the SERPINA1 gene can be undertaken. New technologies arise that may make diagnosis easier and faster. Methods: We developed and evaluated a new diagnostic algorithm based on Luminex xMAP (multi-analyte profiling) technology using Progenika A1AT Genotyping Test. In an initial learning phase, 1979 samples from individuals suspected of having AATD were examined by both, a traditional and a "new" algorithm. In a second phase, 1133 samples were analyzed with the Luminex xMAP only. Results: By introducing a Luminex xMAP based algorithm, we were able to simultaneously identify 14 mutations in SERPINA1 gene (instead of two- S and Z-by using our old algorithm). Although the quantity of IEF assays remained unchanged, the nephelometric measurements and sequencing were reduced by 79% and 63.4%, respectively. Conclusion: The new method is convenient, fast and user-friendly. The application of the Luminex xMAP technology can simplify and shorten the diagnostic workup of patients with suspected AATD.

Results from a large targeted screening program for alpha-1-antitrypsin deficiency: 2003 - 2015.

BACKGROUND: Alpha-1-antitrypsin deficiency (AATD) is an autosomal codominant inherited disease that is significantly underdiagnosed. We have previously shown that the combination of an awareness campaign with the offer of free diagnostic testing results in the detection of a relevant number of severely deficient AATD patients. The present study provides an update on the results of our targeted screening program (German AAT laboratory, University of Marburg) covering a period from August 2003 to May 2015. METHODS: Diagnostic AATD detection test kits were offered free of charge. Dried blood samples were sent to our laboratory and used for the semiquantitative measurement of the AAT-level (nephelometry) and the detection of the S- or Z-allele (PCR). Isoelectric focusing was performed when either of the initial tests was indicative for at least one mutation. Besides, we evaluated the impact of additional screening efforts and the changes of the detection rate over time, and analysed the relevance of clinical parameters in the prediction of severe AATD. RESULTS: Between 2003 and 2015, 18,638 testing kits were analysed. 6919 (37.12 %) carried at least one mutation. Of those, we identified 1835 patients with severe AATD (9.82 % of the total test population) including 194 individuals with rare genotypes. Test initiatives offered to an unselected population resulted in a dramatically decreased detection rate. Among clinical characteristics, a history of COPD, emphysema, and bronchiectasis were significant predictors for Pi*ZZ, whereas a history of asthma, cough and phlegm were predictors of not carrying the genotype Pi*ZZ. CONCLUSION: A targeted screening program, combining measures to increase awareness with cost-free diagnostic testing, resulted in a high rate of AATD detection. The clinical data suggest that testing should be primarily offered to patients with COPD, emphysema, and/or bronchiectasis.

Identification of individuals with alpha-1-antitrypsin deficiency by a targeted screening program.

BACKGROUND: Alpha-1-antitrypsin deficiency (AATD) is significantly underdiagnosed. The early detection of AATD would enable affected persons to make lifestyle changes such as quitting smoking. It was the aim of the study to determine whether the combination of an awareness program with the offer of a cost-free diagnostic test results in the identification of a significant number of individuals with severe AATD. METHODOLOGY: We combined a series of measures to promote awareness with the offer of a diagnostic test at no charge. Test blood was applied to a filter paper and sent to our laboratory. The level of AAT was measured by nephelometry, the presence of the S- or Z-allele was determined by PCR, and phenotyping was performed by isoelectric focusing. RESULTS: During 37 months 17688 testing kits were distributed and 2722 were sent back to our laboratory. We identified 335 patients with severe AATD including 16 individuals with rare genotypes. Prescreening by determining the AAT serum levels by the submitting physician increased the detection rate as compared to similar programs that screened unselected individuals. SUMMARY: These data show that the combination of an awareness program with the offer of free diagnostic testing results in the identification of a large number individuals with severe AATD.