Our study aimed to characterize the PI*SS genotype and its risk for developing lung disease and compare it with the PI*ZZ and PI*SZ genotypes, using the European Alpha-1 antitrypsin Deficiency Research Collaboration (EARCO) international registry [12], which includes a large sample of individuals with the different deficient phenotypes recruited in countries in Europe and America [13]. The gene discussed is SERPINA1; the disease is lung disorder.