Chromosomal rearrangements affecting Chromosome 11q23 result in fusion of the MLL gene (also known as KMT2A) with multiple different fusion partners. One of the most common fusion partners is MLLT3, located at Chromosome 9p22. Presence of a MLL-MLLT3 fusion gene defines a specific AML subtype. This gene fusion is the result of a chromosomal translocation: t(9;11)(p22;q23).
The identification of this gene fusion has diagnostic and prognostic implications.
Fusion of MLL and MLLT3 is associated with intermediate prognosis. Other rearrangements involving MLL have a less favourable prognosis.
This is an assay for non-heritable mutations. It does not raise issues of ethics or consent that are different from most other investigations ordered in the routine care of a patient.
Fluorescent in situ hybridisation (FISH) analysis, using probes designed to detect MLL-MLLT3 gene fusion.
Requesting the test
This test is usually requested by a haematologist or oncologist.
0.5 mL bone marrow in transport media (or 10 mL blood in lithium heparin if blasts >10%).
To help ensure the quality of the test, a genetic test should be done with a dedicated sample whenever possible i.e. a sample collected specifically for that test rather than a sample that is used for multiple tests.
We recommend that the patient or another adult check the labelling of request forms and sample containers.
2 business days.
This test has a Medicare rebate which, subject to the requirements of the Medicare descriptor being met, may cover all or part of the cost.
The Medicare details, including descriptor and schedule fee, are listed under MBS item 73314.