Definition

H3F3A encodes the histone H3.3 variant; the K27M mutation is mostly seen in pediatric/young adult diffuse midline gliomas and triggers oncogenesis by inhibiting the PRC2 complex, reducing global H3K27 trimethylation; it is associated with an extremely poor prognosis (median survival approximately 9 to 12 months). G34R/V mutations are seen in hemispheric pediatric high-grade gliomas.

Gene/region examined

K27M, G34A

Method

DNA analysis

Accepted sample types

Fresh tumor tissue, FFPE

Description

GBM diagnosis.

Inheritance

This is a somatic mutation acquired specifically in tumor tissue; germline transmission has not been reported.

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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