EMPHYSEMA ASSOCIATED WITH COMPLETE ABSENCE OF ALPHA-I-ANTITRYPSIN OF A STOP CODON IN AN ALPHA-I-ANTITRYPSIN-CODING EXON

  • 1 January 1988
    • journal article
    • research article
    • Vol. 42  (1) , 77-83
Abstract
Homozygous inheritance of the null bellingham .alpha.1-antitrypsin (.alpha.1AT) gene is associated with early-onset emphysema, resulting from the lack of .alpha.1AT to protect the lung from neutrophil elastase. Cloning and sequencing of the null bellingham gene demonstrated that the promoter region, coding exons, and all exon-intron junctions were normal except for a single base substitution in exon III, causing the normal lys217 (AAG) to become a stop codon (TAG). Evaluation of genomic DNA of family members by using oligonucleotides directed toward this region demonstrated that the index case had inherited this mutation in a homozygous fashion. Although the consequences to the individual (i.e., emphysema) are identical to those associated with the common homozygous Z mutation, the homozygous null bellingham form of .alpha.1AT deficiency has a very different genetic basis.