Demographic and clinical characteristics of patients with α-antitrypsin deficiency genotypes PI*ZZ and PI*SZ in the Spanish registry of EARCO.

Background: The Spanish registry of α-antitrypsin deficiency (AATD) integrated in the European Alpha-1 Research Collaboration (EARCO) provides information about the characteristics of patients, in particular those with the PI*SZ genotype, which is frequent in Spain.

Method: Individuals with severe AATD defined as proteinase inhibitor (PI) genotypes PI*ZZ, PI*SZ and other rare deficient variants were included from February 1, 2020, to February 1, 2022. The analysis focused on a comparison of the characteristics of PI*ZZ and PI*SZ patients.

Results: 409 patients were included (53.8% men) with a mean±sd age of 53.5±15.9 years. Genotypes were PI*ZZ in 181 (44.7%), PI*SZ in 163 (40.2%), PI*SS in 29 (7.2%) and other in 32 (7.9%). 271 (67.4%) had lung disease: 175 chronic obstructive pulmonary disease (43.5%), 163 emphysema (40.5%) and 83 bronchiectasis (20.6%). Patients with the PI*SZ genotype were younger, more frequently non-index cases and had a lower frequency of respiratory diseases except asthma compared with PI*ZZ patients. Among patients with respiratory diseases, PI*SZ individuals were significantly older both at onset of symptoms and at diagnosis; only asthma was more frequent in PI*SZ than in PI*ZZ individuals. Twelve PI*SZ patients (15.4%) received augmentation therapy compared with 94 PI*ZZ patients (66.2%; p<0.001).

Conclusions: There is a high prevalence of PI*SZ in Spain. Patients with the PI*SZ genotype were older at symptom onset and diagnosis and had less severe lung disease compared with PI*ZZ patients. The prevalence of asthma was higher in PI*SZ, and up to 15% of PI*SZ patients received augmentation therapy.