Definition

PDGFRA is a receptor tyrosine kinase gene mutated in about 5-10% of GISTs; the most common mutation, exon 18 D842V, causes primary imatinib resistance by blocking imatinib binding due to a conformational change in the kinase domain. Exon 12 and other PDGFRA mutations are generally sensitive to imatinib; avapritinib is preferred in D842V-positive patients.

Gene/region examined

PDGFRA Exon 12, PDGFRA Exon 18, PDGFRA Exon 19

Method

DNA analysis

Accepted sample types

Fresh tumor tissue, Paraffin block

Description

Gastrointestinal Tumors (GIST). Response to drug therapy: Gleevec (Imatinib).

Inheritance

Typically somatic; germline PDGFRA mutations have also been described in rare familial GIST syndromes.

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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