Definition

A nucleotide change in exon 14 of the JAK2 gene causes a valine to phenylalanine (V617F) substitution in the JH2 pseudokinase domain. This change constitutively activates the JAK/STAT signaling pathway independent of erythropoietin. It is detected in approximately 90 to 98% of polycythemia vera (PV) cases and in 50 to 60% of essential thrombocythemia and primary myelofibrosis cases.

Method

DNA analysis

Accepted sample types

Blood (EDTA), bone marrow (EDTA)

Description

Monitoring response to drug treatment and relapse in various cancer types. Essential Thrombocythemia (ET), Hypereosinophilic Syndrome (HES), Chronic Myelomonocytic Leukemia (CMML), Myelodysplastic Syndromes (MDS), Myelofibrosis with Myeloid Metaplasia, Neutrophilic Leukemia (NL), Polycythemia Vera (PV), Mast Cell Leukemia, Mastocytosis.

Inheritance

This is somatic, a driver mutation acquired in the hematopoietic stem cell; it 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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