alpha-1-antitrypsin deficiency in liver disease: the extent of the problem.

A prospective screening program was undertaken at the Royal Free Hospital, London, to ascertain the incidence of alpha-1-antitrypsin (AAT) deficiency in patients with liver disease. Quantitative determinations of serum alpha-1-antitrypsin were performed on 469 patients with hepatobiliary disease and 98 subjects with no known liver disease. Sera with low values of AAT were phenotyped. The homozygous state was rare and comprised only 1% of the patients with liver disease. All of the 5 homozygous deficient (ZZ phenotype) patients had a history of neonatal liver disease. Other phenotypes (partial deficiency) were found in 4.7% of patients with liver disease and 6.1% of subjects with normal liver function. Types of liver disease in the patients with other phenotypes were widely varied. Routine determination of serum AAT level and phenotype and special staining for AAT in liver biopsies in all adults with liver disease appears unnecessary. Investigation of possible AAT deficiency should be carried out, however, in children and young adults, in those with a history of neonatal liver disease, and possibly in all patients with liver disease of unknown aetiology.