Rapid Screening for α1-Antitrypsin Z and S Mutations,

α1-Antitrypsin (A1AT) is a serine protease inhibitor required for the prevention of proteolytic tissue damage, principally in the lung, by neutrophil elastase released by inflammatory cells (1). While severe A1AT deficiency is the major factor leading to emphysema and related pulmonary diseases, it is also associated with neonatal hepatitis and cirrhosis (1)(2). A1AT deficiency is an autosomal codominant disorder with a prevalence of about 1:3000 in Caucasians (3). The A1AT gene has 7 exons spanning ∼12 kb. The most common gene defect resulting in A1AT deficiency is that of a protease inhibitor (PI)-system Z mutation Glu342 to Lys, which is a single base substitution of G to A in exon 5 (4)(5). The S mutation, a Glu264 to Val change, is caused by an A to T substitution in exon 3 (6). Individuals with SS are unaffected, SZ may be symptomatic, and ZZ results in the most severe clinical symptoms. In Caucasians the prevalence of the S allele ranges from 5% to 10% and Z allele 2% to 5% depending on geographical location (7)(8). Although the frequencies are unknown in the Chinese, geographical variability of the A1AT alleles is evident by phenotypic analysis of the PI variants (9 …