26408 Alpha-1-Antitrypsin Phenotype, Serum (A1APP)

​A1A Phenotyping

a-1-Antitrypsin, Phenotype

AAT Phenotyping

Alpha 1 Antitrypsin

Anti-Alpha-1-Trypsin

Antitrypsin

Antitrypsin, Phenotype

Pi Typing (Alpha-1-Antitrypsin Phenotyping)

Protease Inhibitor Allo Typing

Alpha-1-Antitrypsin Reflex

 Alpha-1-Antitrypsin

 Alpha-1-Antitrypsin Phenotype

​Identification of homozygous and heterozygous phenotypes of the alpha-1-antitrypsin deficiency

​Gross Lipemia

This assay identifies the phenotype of the circulating alpha-1-antitrypsin (A1A) protein. If the patient is already on replacement therapy, the phenotype will detect patient and replacement protein.

If 2 bands are seen, such as an M band and a Z bands, it is reported as MZ (eg, heterozygous).

If 1 band is seen, such as the Z band and the quantitative level is consistent with a homozygote, the phenotype is assumed to be homozygous and is reported as ZZ.

Alpha-1-antitrypsin (A1A) is the most abundant serum protease inhibitor and inhibits trypsin and elastin, as well as several other proteases. The release of proteolytic enzymes from plasma onto organ surfaces and into tissue spaces results in tissue damage unless inhibitors are present. Congenital deficiency of A1A is associated with the development of emphysema at an unusually early age and with an increased incidence of neonatal hepatitis, usually progressing to cirrhosis.

Most normal individuals have the M phenotype (M, M1, or M2). Over 99% of M phenotypes are genetically MM. In the absence of family studies, the phenotype (M) and quantitative level can be used to infer the genotype (MM). The most common alleles associated with a quantitative deficiency are Z and S.

There are greater than 40 alpha-1-antitrypsin (A1A) phenotypes (most of these are associated with normal quantitative levels of protein). The most common normal phenotype is M (M, M1, or M2), and greater than 90% of Caucasians are genetically homozygous M (MM).  A1A deficiency is usually associated with the Z phenotype (homozygous ZZ), but SS and SZ are also associated with decreased A1A levels.