Genotyping of alpha-antitrypsin in ten Croatian families

Objectives: The aims of the study were to determine or-antitrypsin (AAT) ge notype by a simple DNA-based method and to investigate the association of A AT genotype and serum AAT concentration in a group of ten families. Methods and results: AAT genotype was determined by PCR-RFLP and serum conc entration by radial immunodiffusion in samples from each member of ten fami lies (mother, father, and child/ children). In the group of parents, five n ormal genotypes, Pi MM, with a normal serum AAT concentration, and fifteen Pi MZ genotypes, four of them with slightly decreased (43%-66% of the mean) AAT concentration were detected. In the group of children, particular geno types followed the mode of inheritance. There were eight Pi MZ, three of th em with slightly decreased (52%-60% of the mean) AAT concentration, and fiv e Pi ZZ genotypes with considerably decreased (24%-45% of the mean) AAT con centration. Conclusions: PCR-RFLP is the method of choice for AAT genotyping. AAT conce ntration is not a reliable biochemical marker of AAT deficiency. Determinat ion of AAT genotype in family studies allows the risk of deficient allele i nheritance to be followed up and assessed. Early diagnosis of a deficient A AT genotype contributes to the success of currently widely available AAT re placement therapy. Copyright (C) 2000 The Canadian Society of Clinical Chem ists.