Definition

The KMT2A gene (formerly known as MLL) is located at 11q23 and encodes a histone methyltransferase that regulates chromatin structure. Rearrangement of this gene to form a fusion with numerous different partner genes (most commonly AFF1, MLLT1, MLLT3) is seen in approximately 10% of acute leukemias; it is the driver mutation in 80% of infant leukemias.

Method

FISH analysis

Accepted sample types

Peripheral blood, bone marrow (heparin)

Description

Diagnosis and monitoring of ALL and AML.

Inheritance

KMT2A rearrangements are somatic (acquired) genetic events; they occur in infant leukemias and in leukemias secondary to prior chemotherapy (particularly topoisomerase II inhibitors) and do not show inherited transmission.

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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