Alpha1-antitrypsin deficiency with M-like phenotype.

Abstract
A patient with a low serum concentration of .alpha.1-antitrypsin (0.1 g/l) but with an M-like phenotype is described. Her parents and 2 sibs have a PiM phenotype, but all except the father have approximately half-normal levels of .alpha.1-antitrypsin: The M-like variant apparently cannot be distinguished from M-.alpha.1-antitrypsin, when it occurs with M in heterozygotes. The proposita has severe airways obstruction and emphysema, and her father has moderate chronic obstructive pulmonary disease. The mother and 2 sibs are healthy.