Alpha 1-antitrypsin alleles in patients with pulmonary emphysema, detected by DNA amplification (PCR) and oligonucleotide probes.

Alpha 1-antitrypsin (AAT) deficiency is a serious predisposing factor for the development of pulmonary emphysema. Twelve representative Danish families were studied. AAT typing was performed as a comparative study between the traditional protein typing by isoelectrical focusing and the deoxyribonucleic acid (DNA) technique of enzymatic amplification and subsequent typing with radioactively labelled oligonucleotide probes. On the basis of clinical and radiological signs of pulmonary emphysema, 25 patients were selected. AAT typing was performed by use of the two techniques in combination, in search for new point-mutations among the patients. Results obtained with the two techniques were discordant in one patient, suggesting an unknown variant. The unexpectedly high PiZ frequency of 0.22 found in the study group is discussed.