Physiological studies in a large sibship with antitrypsin deficiency.

A large sibship demonstrated the severe consequences of alpha-1 antitrypsin deficiency. Of II living sibs 6 were homozygous deficient (Pi type ZZ) and 5 heterozygous (Pi type MZ). The homozygous group showed severe obstructive ventilatory impairment by spirometry, marked abnormality of airway resistance and specific conductance with striking pulmonary hyperinflation. The heterozygous deficient group demonstrated a less severe obstructive defect by ventilation measurements with only marginal abnormality of airway resistance, specific conductance, and normal lung volumes. The evidence suggests that both the heterozygous and the homozygous states of alpha-1 antitrypsin deficiency are lung damaging.