MVarallo: A New MLike Alpha 1-Antitrypsin-Deficient Allele

Abstract

A 73-year-old never-smoker woman with chronic bronchitis, increasing dyspnoea, and airflow limitation with a FEV1 of 49% of predicted value had low serum level of alpha-1-antitrypsin (69 mg/dL, normal range 150-350). Isoelectric focusing showed an Mlike pattern. Direct sequencing showed, in the second exon, a particular DNA alteration localized between codon 41 and codon 51: a region of 30 base pairs (bp) was completely deleted and substituted by a 22-bp sequence. The resulting loss of 8 bp yields, in the second exon, a 70-71 stop codon. This new Mlike variant was denominated MVarallo from the site where it was discovered.

Prevalence and phenotype of subjects carrying rare variants in the Italian registry for alpha1-antitrypsin deficiency

“…allele is characterised by a 30 bp deletion accompanied by a 22 bp fragment insertion at the 41-51 codon region in exon II,25 whereas the Q0 cairo is a null variant raised on the M1(Val213) base allele, characterised by a ART transversion at codon 259, exon II, resulting in a stop codon instead of a Lys codon (GenBank accession number AY 256958).…”