A Fast Amplification-Reverse Hybridization Assay Kit to Detect the Most Frequent Deficient Variants in the Alpha-1-Antitrypsin Gene

Abstract

Background: There is worldwide growing awareness of alpha-1-antitrypsin deficiency (AATD), a major hereditary disorder in Caucasians. The gold standard for its laboratory diagnosis is thin-layer isoelectric focusing, which should be performed in reference laboratories. Objectives: The aim of this study was to check the characteristics of a commercially available amplification-reverse hybridization assay kit in detecting at a molecular level the alpha-1-antitrypsin (AAT) Z and S variants, i.e. the most frequent variants associated with AATD, by comparing its performance with DNA restriction fragment length polymorphism. Methods: We studied samples from 36 subjects enrolled in the Italian National Registry for Severe Alpha-1-antitrypsin Deficiency. Based on previous plasma isoelectric focusing typing, we selected samples with the following phenotypes: MM (9 samples), MS (9 samples), SZ (3 samples), MZ (11 samples), ZZ (3 samples), and a rare variant (1 sample). DNA was extracted by the standard method. The presence of the AAT Z and S gene variants was determined by the amplification-reverse hybridization test kit, following the manufacturer’s instructions, and by the restriction fragment length polymorphism technique, according to established procedures. Results: We found that the identification of the AAT Z and S gene variants obtained by the amplification-reverse hybridization test kit was completely in agreement with that obtained by the restriction fragment length polymorphism technique. Conclusions: We conclude that the test kit provides a fast, easy and unambiguous identification of Z and S alleles. Because of its transferability to routine laboratories, the test kit may be useful in identifying cases of severe AATD, thus resulting in increasing awareness of this rare disorder.