What is the genetic abnormality in patients with alpha-1-antitrypsin deficiency?
The alpha-1-antitrypsin allele, which is present on both genes in patients with alpha-1-antitrypsin deficiency, gives rise to an alpha-1-antitrypsin gene protein type, called PiZ protein. This results in an alpha-1-antitrypsin protein phenotype called the PiZZ phenotype. Confirmation of the PiZZ phenotype can be performed in the laboratory using isoelectric gel separation techniques. The PiZ protein cannot be secreted by hepatocytes, and, hence, patients have very low levels of serum alpha-1-antitrypsin (typically <10% of normal). Retained protein leads to decreased liver function and cellular damage.
