alpha-1 Antitrypsin phenotypes by isoelectric focusing in a metropolitan southern Chinese population

Aims/Background-alpha -1 Antitrypsin (alpha 1AT) is an abundant protease in hibitor in human plasma. Its phenotypic variability has been reported to be associated with pulmonary emphysema and chronic liver diseases. However, a lpha 1AT deficiency is an uncommon condition in the Chinese population. The aim of this study was to describe the phenotypic distribution of alpha 1AT in a southern Chinese population. Methods-A total of 1085 healthy blood donors underwent alpha 1AT phenotypin g by isoelectric focusing. Results-Two thirds (66.1%) were homozygous for either M1 or M2, whereas 32. 6% were heterozygous for two different M phenotypes. The frequency of allel ic variants was only 0.007, and deficiency variants were absent. Compared w ith earlier studies on southern Chinese populations, this study found a low er frequency of M2, and a higher number of allelic variants, including E, L , N, P, and S. This phenomenon can be attributed to population migration an d mixing. Conclusions-An understanding of the alpha 1AT pattern is important for eval uating the predisposition of the population to selected clinical diseases.