Genotype | AAT level¶ | Lung disease | Liver disease |
Unaffected (no variant or mild deficiency variants only) | |||
PI*MM | 20 to 53 micromol/L 100 to 220 mg/dL |
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PI*SS | 15 to 33 micromol/L 100 to 200 mg/dL |
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Heterozygous for SERPINA1 disease variants | |||
PI*MZ or PI*SZ | 17 to 33 micromol/L 90 to 210 mg/dL or 8 to 16 micromol/L75 to 120 mg/dL |
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Homozygous or compound heterozygous for SERPINA1 disease variants | |||
PI*ZZ | 2.5 to 7 micromol/L 20 to 45 mg/dL |
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Null | 0 micromol/L 0 mg/dL |
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PI*FFΔ | 20 to 53 micromol/L 100 to 220 mg/dL |
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AAT: alpha-1 antitrypsin; AATD: alpha-1 antitrypsin deficiency; ANCA: antineutrophil cytoplasmic antibody; ELISA: enzyme-linked immunosorbent assay; PI: protease inhibitor (another name for AAT).
¶ Molarity is generally determined by ELISA; concentration in mg/dL can be determined by nephelometry. The protective threshold for AAT is considered to be 11 micromol/L (57 mg/dL) or above.
Δ The F allele (Arg223Cys) is very rare. It produces normal AAT protein levels, but the protein is dysfunctional with markedly impaired antineutrophil elastase activity. PI*FF individuals are at risk for emphysema; however, assaying their serum AAT level may be insufficient to diagnose AATD.Do you want to add Medilib to your home screen?