Alpha 1 antitrypsin deficiency prevalence measured by genetic testing with salivary swab in patients with chronic airway obstruction

Abstract

Introduction: Alpha 1 antitrypsin deficiency (DAAT) is responsible for 1-2% of all cases of emphysema but unfortunately only 10% of patients with severe DAAT are diagnosed and more than 95% of patients with emphysema have not been assessed. This study aim is to determine the prevalence of DAAT by simultaneous identification and genotyping of S, Z and other variants of the SERPINA1 gene.₁

Material and Methods: Descriptive cross-sectional study determining prevalence of DAAT in patients with obstructive airway disorder measured by spirometry. An oral sample collector (Oracollect DNA®, a registered trademark of DNA Genotek) was used for saliva swab. It consists of placing the swab in the mouth, gently scraping 10 times each lower gum with back and forth movements. The tube was then held upright by inserting the swab in it, closing it and then vigorously shaken 15 times. It was ensured that the patient had not eaten food or drinks and without smoking 30 minutes before its collection. The biological sample was sent to Progenika Biopharma, S.A. ("Progenika") for processing.

Results: The sample was 200 patients, 57% men with a mean age of 65 ± 14.7 years, mean FEV1 was 1800 ± 750mL (70±10%). Positive results were obtained in 30 patients (15%), among which 21 presented MS genotype, 7 of them MZ, one MI and one MF.

Conclusions: Diagnosing DAAT with an easily accesible and non-invasive genotyping salivary swab may take a role for identification of index cases and, subsequently, for apropriate diagnosis and treatment.

₁Ferrarotti I., Ottaviani S. Laboratory Diagnosis. In:Strnad P., Brantly M., Bals R. ERS monograph α1-Antitrypsin Deficiency 2019.(p.39-51)