Introduction: It is estimated that in about 1% of all liver transplant candidates liver cirrhosis is caused by hereditary homozygous α1‑antitrypsin (AAT) deficiency.

Objectives: The aim of the study was to evaluate the role of heterozygous AAT deficiency in the development of liver cirrhosis leading to liver transplantation.

Patients and methods: In the years 2009–2011, we conducted a prospective study of 304 consecutive patients (men, 57%) scheduled for orthotopic liver transplantation. AAT phenotyping and the clinical assessment of hepatic and cardiopulmonary functions were performed in all subjects.

Results: The most common causes of liver cirrhosis were viral hepatitis (21%) and alcohol abuse (12%). Normal protease inhibitor (Pi) MM phenotype was observed in 284 patients. The PiMZ phenotype was detected in 11 subjects (4%), which indicates its higher prevalence in patients with liver cirrhosis compared with the general population (2%). PiMS phenotype was found in 6 patients (2%), and this value was similar to that observed in the Polish population. In 3 patients, less common phenotypes were observed: MP, IM, and MX.

Conclusions: The PiMZ phenotype may be an independent risk factor for the development of liver cirrhosis along with the most common causes, namely, viral hepatitis and alcohol abuse.