Definition

The t(9;22)(q34;q11) translocation joins the ABL1 gene with the BCR gene to form the abnormal BCR-ABL1 fusion gene; the shortened chromosome carrying this fusion is called the "Philadelphia chromosome." The fusion protein is a constitutively active tyrosine kinase and is the shared molecular mechanism in CML and Ph+ ALL; it is sensitive to tyrosine kinase inhibitors such as imatinib.

Method

FISH analysis

Accepted sample types

Peripheral blood, bone marrow (heparin), blood (heparin)

Description

Diagnosis and monitoring of CML, ALL and AML.

Inheritance

The BCR-ABL1 fusion is an acquired/somatic change that occurs later in blood cells; it is not present in the germline and is not inherited.

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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