Genotyping diagnosis of alpha-1 antitrypsin deficiency in Saudi adults with liver cirrhosis

The acute phase protein alpha-1 antitrypsin (AAT) is mainly produced in liver cells. AAT deficiency affects the lungs and liver. We conducted a case-control study to define a valuable method for the proper diagnosis of alpha-1 antitrypsin deficiency (AATD), as well as the association of liver cirrhosis with AATD in Saudi adults. Blood samples from 300 liver cirrhosis patients and 400 controls were analyzed according to serum AAT concentration, phenotyping, and genotyping. Nephelometry was used for AAT quantification, isoelectric focusing electrophoresis was used for phenotyping detection, and real-time PCR was used for genotyping to determine the Z and S deficiency alleles. This study highlights the accuracy of using genotyping in addition to AAT quantification, since this technique has proven to be successful in the diagnosis of AATD for 100% of our cases. A significant deviation in AAT genotypes frequencies from the Hardy–Weinberg equilibrium in the adult cirrhosis group occurred due to a higher observed frequency than expected for the Pi ZZ homozygous genotype. Pi ZZ in adults may be considered as the risk factor for liver cirrhosis. However, we could not establish this relationship for heterozygous AATD genotypes (such as Pi MZ and Pi SZ).