[Alpha 1-antitrypsin deficiency: a review with special reference to the significance of heterozygous deficiency].

Homozygous deficiency of alpha-1 antitrypsin is the most common inborn error or metabolism in Europe. Severe deficiency of this major protease inhibitor in serum is associated with chronic obstructive lung disease, chronic liver disease in adults and neonatal hepatitis. An overview is given of the role of heredity, and the diagnostic criteria and clinical and histological findings in this disorder. Emphysema seems to be caused by the free elastolytic activity of white cells, leading to the degradation of elastin. The pathophysiology of liver disease - less well understood - is discussed with special emphasis on the importance of heterozygous alpha-1 antitrypsin deficiency. Exogenous noxae seem to play an important role in the pathogenesis of heterozygous deficiency. In view of the 7% frequency of heterozygous alpha-1 antitrypsin deficiency in the European population and the role of noxae in the development of pulmonary and liver diseases, improved prophylaxis is mandatory.