SERPINA1 and liver disorder: As a result of codominant gene expression, individuals heterozygous for the Z allele (i.e. PI*MZ individuals) typically show AAT levels of 11–28 μM (62–151 mg·dL−1) [7], slightly below the normal range, and may, therefore, also be at some risk of developing lung and/or liver disease in combination with other risk factors [8].