Definition

The SERPINA1 gene encodes alpha-1-antitrypsin (AAT), a protein produced in the liver that inhibits neutrophil elastase in the lungs; the most common pathogenic allele, PIZ, produces an abnormal protein that is both functionally inadequate and polymerizes and accumulates in liver cells, causing damage. PIZZ homozygotes may develop liver dysfunction and chronic obstructive pulmonary disease after the age of 30; smoking accelerates lung involvement.

Gene/region analyzed

SERPINA1 - S and Z alleles

Method

Sequence analysis

Accepted sample types

EDTA blood, AF, CVS

Inheritance

Hereditary, autosomal codominant (gene-dosage effect).

Related Tests

Inheritance Patterns

Describes how a genetic condition is passed on within a family. There are five main patterns

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Carrier (Heterozygous / Homozygous)

Why it matters: In autosomal recessive inheritance, when each parent is a carrier (while both appear healthy), the chance of their child being born with the disease is 25% in each

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VUS (Variant of Uncertain Significance)

This is the situation where the test has detected a change in the DNA, but the role of this change in the development of disease is unconfirmed.

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How to Read a Genetic Test Result (Positive / Negative / VUS)

A genetic test result falls into three main categories

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Types of Genetic Tests

A genetic test is a type of medical test that detects changes in genes, chromosomes or proteins. Today there are more than 77,000 genetic tests available.

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