Alpha-1-antitrypsin: the PiM subtypes and serum concentrations in Finnish newborns.

Pi phenotypes were classified by isoelectric focusing of the sera of 200 full-term Finnish newborns at the age of 3--5 days. The phenotype PiM was found in 95% of the neonates. The frequencies of the alleles PiM1, PiM2 and PiM3 were 0.682, 0.189 and 0.129, respectively. The serum concentration (mean +/- SD) of alpha-1-antitrypsin (alpha 1-AT) in the whole study group was 2.72 +/- 0.61 g/l. The concentration of alpha 1-AT in the newborns with the phenotype PiM3 (1.79 +/- 0.65 g/l) was significantly lower (p less than 0.025) than in other PiM subtypes. No difference in serum concentrations of alpha 1-AT between boys (2.78 +/- 0.66 g/l) and girls (2.66 +/- 0.55 g/l) was observed.