Phenotypes of alpha 1 antitrypsin in Karachi, Pakistan

Objective: To determine serum level of the protease inhibitor, to identify phenotypes and determine their frequencies. Study Design: A prospective study. Setting: PMRC, Research Centre, JPMC and the Aga Khan University Hospital, Karachi. Subjects: Healthy adults without history of peptic ulcer disease and a normal endoscopy. Methodology: Quantitative measurement of serum alpha 1 AT was carried out by radial immunodiffusion, phenotyping by iso-electric focusing and confirmation of phenotypes by immuno-fixation and DNA analysis technique. Results: Serum alpha 1 AT was low in 13.4% of the subjects. MM phenotype predominated followed by SZ, SS,MZ and ZZ. DNA diagnosis accurately resolved the phenotypes as S and Z. Conclusion: Frequency of phenotype associated with total and intermediate deficiency is less in the population.