The flaccid lung syndrome and alpha 1-protease inhibitor deficiency

We examined breathing mechanics and alpha 1PI deficiency in 1,850 unrelated male subjects with various lung complaints. The loss in lung elasticity appeared to be significantly more pronounced in ZZ individuals as compared to MM, MS and also MZ individuals. The MZ group did not differ significantly in this respect from MM individuals. This implies that the excess risk of developing a flaccid lung (C greater than 1 kPa-1) due to the partial alpha 1-antitrypsin deficiency is negligible. PI MZ and PI ZZ frequencies are significantly higher in the population with flaccid lung compared to control subjects. Furthermore, it was found that the increase in residual volume in smokers is independent of the PI type.