Lung function in alpha-1-antitrypsin deficient sisters.

Two sisters were found to homozygous for alpha-1-antitrypsin deficiency. One was disabled by breathlessness and had advanced clinical and radiological emphysema which was confirmed on lung function testing. The other, of similar age and smoking history, was symptom-free with a normal chest radiograph. She had a slightly increased airways resistance, a reduced gas transfer, a bilaterally reduced apex--base perfusion gradient and a small but generalized increase in physiological dead space in all zones. The minor pulmonary and vascular abnormalities present in the younger sibling suggest that we are witnessing early changes in the evolution of the panacinar emphysema characteristic of alpha-1-antitrypsin deficiency. The reason for the different rates of progress of the disease in these two sisters is not understood.