[Electrophoretic alpha 1-antitrypsin variation in the Swiss population].

Two Swiss populations (population 1: Switzerland, n = 1041; population 2: population of the mountain village of Törbel, n = 273) have been phenotyped in the Pi-system (alpha 1-antitrypsin system) by isoelectrofocusing (pH 4-6 and 4-5, Ampholine plates). 20 Pi-phenotypes have been detected, which are genetically determined by at least 9 alleles. In population 1 (Switzerland) 17 Pi-phenotypes have been found, among them the relatively rare Pi-phenotypes Pi M1T, Pi M1F, Pi M1I, Pi M2S, Pi M2I, Pi M3M3, Pi M3F, Pi SS, Pi SF, Pi SZ and Pi ZZ. The detection of the PiT-allele and of the clinically relevant phenotype Pi ZZ in this population requires a special interest. The relatively isolated population 2 (Törbel) in the Swiss Alps seems to be characterized by a lower number of Pi-phenotypes and by an increased frequency of the PiE-allele compared to the whole Swiss population. Detailed data about the demography and the history of this population strengthen the hypothesis that in particular genetic drift (founder principle) and isolation are responsible for this significant distribution of the Pi-phenotypes.