Determination of Alpha 1-Antitrypsin Phenotypes and Genotypes in Iranian Patients

Alpha 1-antitrypsin (AAT) or alpha 1-protease inhibitor (PI) is the principal inhibitor of proteolytic enzyme in serum. Its phenotypic variability has been reported to be associated with liver, lung diseases and rheumatoid arthritis in humans. There is much documentation about high risk phenotypes of PI in some regions of the world, however, there are no reliable reports on these phenotypes and genotypes and their related diseases in Iranian population. The aim of this study was to determine PI phenotypes and genotypes in Iranian patients suffering from PI deficiency. For this purpose, whole blood samples from 307 patients suspected of diseasesrelated to PI deficiency, and 156 healthy persons were examined. PI phenotypes and genotypes were determined by isoelectric focusing (IEF) and polymerase chain reactionrestriction fragment length polymorphism (PCR-RFLP), respectively. Allele frequencies from patients and normal subjects were compared. For reliability, a family study of the patients was also carried out. The PI phenotype frequencies of all six possible combinations of M, S and Z haplotypes in patients were: MM, 77.20%; MS, 6.18%; MZ, 7.17%; SS,3.91%; ZZ, 4.56%; SZ, 0.98% and in normal subjects were: MM, 78.20%; MS, 5.76%; MZ, 15.38%; SS, 0.64%; 0% for ZZ and SZ. Analysis of data showed that there was a significant difference between patients (with liver, lung diseases and rheumatoid arthritis) and control subjects (p< 0.05). In Conclusion, the allelic frequencies of S and Z in the patient group were 7.49% and 8.63%, while in the normal subjectswere 5.13% and 4.17%, respectively. This is the first report of the prevalence of high risk alleles (Z and S) in patients suspected of PI deficiency and related diseases in Iran.