Alpha 1-antitrypsin deficiency other diagnostic studies

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mazia Fatima, MBBS [2]

Overview

Patients with low or borderline serum levels are tested with phenotyping (serum levels < 100 mg/dL) by isoelectric focusing (IEF) is the most commonly used method to definitively detect the alpha1-antitrypsin phenotype that indicates a risk for AATD. Genotyping uses DNA extracted from circulating mononuclear blood cells that utilizes DNA amplification techniques with melt-curve analysis.

Other Diagnostic Studies

Phenotyping

Patients with low or borderline serum levels are tested with phenotyping (serum levels < 100 mg/dL) by isoelectric focusing (IEF) is the most commonly used method to definitively detect the alpha1-antitrypsin phenotype that indicates a risk for AATD.^[1]^[2]

Phenotyping is required to confirm AATD. Do not initiate alpha1-antitrypsin replacement therapy without testing.

PiZZ phenotype is responsible for nearly all cases of AATD emphysema and liver disease.
PiSZ and PiZ/Null are other phenotypes associated with alpha1-antitrypsin emphysema and liver disease.
PiNull/Null is not associated with liver disease but is associated with alpha1-antitrypsin deficiency emphysema.

Genotyping

Genotyping uses DNA extracted from circulating mononuclear blood cells that utilizes DNA amplification techniques with melt-curve analysis.

References

↑ Ljujic M, Topic A, Divac A, Nikolic A, Petrovic-Stanojevic N, Surlan M, Mitic-Milikic M, Radojkovic D (2008). “Isoelectric focusing phenotyping and denaturing gradient gel electrophoresis genotyping: a comparison of two methods in detection of alpha-1-antitrypsin variants”. Transl Res. 151 (5): 255–9. doi:10.1016/j.trsl.2008.02.002. PMID 18433707.
↑ Al-Jameil N, Hassan AA, Buhairan A, Hassanato R, Isac SR, Al-Otaiby M, Al-Maarik B, Al-Ajeyan I (2017). “Genotyping diagnosis of alpha-1 antitrypsin deficiency in Saudi adults with liver cirrhosis”. Medicine (Baltimore). 96 (6): e6071. doi:10.1097/MD.0000000000006071. PMC 5313019. PMID 28178162.

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[pmid18433707-1] Ljujic M, Topic A, Divac A, Nikolic A, Petrovic-Stanojevic N, Surlan M, Mitic-Milikic M, Radojkovic D (2008). “Isoelectric focusing phenotyping and denaturing gradient gel electrophoresis genotyping: a comparison of two methods in detection of alpha-1-antitrypsin variants”. Transl Res. 151 (5): 255–9. doi:10.1016/j.trsl.2008.02.002. PMID 18433707.

[pmid28178162-2] Al-Jameil N, Hassan AA, Buhairan A, Hassanato R, Isac SR, Al-Otaiby M, Al-Maarik B, Al-Ajeyan I (2017). “Genotyping diagnosis of alpha-1 antitrypsin deficiency in Saudi adults with liver cirrhosis”. Medicine (Baltimore). 96 (6): e6071. doi:10.1097/MD.0000000000006071. PMC 5313019. PMID 28178162.

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