Although several degrees of AAT deficiency are quite common worldwide, severe deficiency (i.e. AAT serum levels below 11 μmol or 50 mg/dL) represents a rare condition affecting 1 per 2,000-5,000 Caucasian individuals of Western European origin, with about a quarter or half of them developing clinically significant diseases [1,2]. This evidence concerns the gene SERPINA1 and alpha 1-antitrypsin deficiency.