In parallel with the discovery of new alleles increasing the complexity of the Pi system, technical refinements have made the classification of an individual with respect to his Pi system relatively simple. Isoelectrofocusing in polyacrylamide
gels
is
advantageous method in analyzing plsystem because of ease of performance, high resolution and reproducibility. Most individuals have the PiMM phenotype resulting in normal plasma α1-antitrypsin (α1-AT) levels. The classical α1-AT deficiency is
designated as Pizz in its homogygous form and has 15% of normal plasma α1-AT level, which is known to be associated with increased risk of cirrhosis and primary liver cancer. But there is still debate as the cause of this asseciated liver
disease.
This
study is aimed to know the distribution and contribution of structural variants of α1-AT in South Korean patients with chronic liver diseases incuding hepatocellular carcinoma. One hundred thirty nine patients with chronic liver diseases or
hepatocellular carcinoma were studied. Blood samples were taken from each. Phenotypes of α1-AT were determined by electrofocusing in polyacrylamide gel electrophoresis. The results obtained were as follows.
None of the cases showed deficiency or null variant of α1-AT in patients with chronic liver diseases, but two cases with hepatocellular carcinoma showed MS phenotype.
About half of the cases with chronic liver disease and hepatocellular carcinoma showed homologous polymorphism of α1-AT phenotype suballeles such as M1M1, M2M2 and M3M3.
The distribution of the structural variants of α1-AT phenotype in patients with chronic liver diseases and hepatocellular carcinoma were in order as follows: M1M1(51.8%), M1M2 (24.5%), M2M2 (7.9%), M3M3 (6.5%), M1M3 (5.8%), M3M3 (2.2%) and M1S
(1.3%).
In conclusion, none of the cases with chronic liver diseases showed deficiency or null typed structural variants of α1-AT, but there were two cases with M1 S phenotype among the 39 patients with hepatecellular carcinoma. Therefore, genetically
determined α1-AT deficiency seems to be not etiologically important in South Korean patients with chronic liver disease.
|