SERPINA1 and hyperinsulinemic hypoglycemia, familial, 4: Some studies provide evidence of an association between the heterozygous Z allele alpha-1-antitrypsin phenotype and end stage liver disease of different aetiology (19–22), but other studies (including ours) failed to identify an association between heterozygous MZ alpha-1antitrypsin deficiency and cirrhosis (23–27).