Definition

The F12 gene encodes factor XII (Hageman factor); in HAE type III (HAE-FXII), the form with normal C1 inhibitor levels, mutations in the F12 gene (particularly variants that disrupt glycosylation at Thr309) increase the autoactivation of factor XII and lead to excessive bradykinin production. Recurrent episodes of swelling occur in the limbs, face, tongue, larynx and genital area; the disease has been described largely in women, and attacks are triggered by estrogen.

Gene/region analyzed

F12 - Exon 1, F12 - Exon 2, F12 - Exon 3, F12 - Exon 4, F12 - Exon 5, F12 - Exon 6, F12 - Exon 7, F12 - Exon 8, F12 - Exon 9, F12 - Exon 10, F12 - Exon 11, F12 - Exon 12, F12 - Exon 13, F12 - Exon 14

Method

Sequence analysis

Accepted sample types

EDTA blood, AF, CVS

Inheritance

Hereditary, autosomal dominant (AD), with variable expressivity (particularly in women).

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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