Rapid analysis of alpha(1)-antitrypsin PiZ genotype by a real-time PCR approach

alpha(1)-Antitrypsin (AAT) deficiency is a common inherited cause of emphys ema and cirrhotic liver disease. Current laboratory diagnosis of Pi (protei nase inhibitor) status by protein analysis depends on the availability of b lood samples and has a limited accuracy. Single-strand conformational polym orphism (SSCP) analysis and direct DNA sequencing can be performed from blo od cells or from tissue samples, but it is a time-consuming procedure not s uitable for screening purposes. We used a Light-Cycler assisted PCR approac h to identify the PiZ mutation and to determine hetero- and homozygous carr ier status from whole blood and from paraffin embedded archival tissue spec imens. The results were compared to those obtained by standard PCR amplific ation followed by SSCP and direct DNA sequencing. Light-Cycler assisted PCR identified heterozygous PiZ mutations in 16 samples, a homozygous PiZ stat us in three cases, and wild-type PiM in five control samples. In all cases the results were confirmed by SSCP and direct DNA sequencing. Light-Cycler assisted PCR has a high detection rate for the PiZ mutation. It can be perf ormed from blood or from fixed archival tissues, requires only small amount s of DNA, and allows a rapid diagnosis on a high output level.