AFF4

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Reviewed November 2015

What is the official name of the AFF4 gene?

The official name of this gene is “AF4/FMR2 family, member 4.”

AFF4 is the gene's official symbol. The AFF4 gene is also known by other names, listed below.

Read more about gene names and symbols on the About page.

What is the normal function of the AFF4 gene?

The AFF4 gene provides instructions for making part of a protein complex called the super elongation complex (SEC). During embryonic development, the SEC is involved in an activity called transcription, which is the first step in the production of proteins from genes. By re-starting the transcription of certain genes after pauses that normally occur during the process, the SEC helps ensure that development proceeds appropriately before birth.

How are changes in the AFF4 gene related to health conditions?

CHOPS syndrome - caused by mutations in the AFF4 gene: Mutations in the AFF4 gene cause CHOPS syndrome, a disorder involving multiple abnormalities that are present from birth (congenital). The name "CHOPS" is an abbreviation for a list of features of the disorder including cognitive impairment, coarse facial features, heart defects, obesity, lung (pulmonary) involvement, short stature, and skeletal abnormalities.

The AFF4 gene mutations identified in people with CHOPS syndrome change single protein building blocks (amino acids) in the AFF4 protein. These mutations are thought to result in an AFF4 protein that is not broken down when it is no longer needed, so more AFF4 protein is available than usual. The excess AFF4 protein interferes with normal pauses in transcription. This dysregulation of transcription leads to problems in the development of multiple organs and tissues, resulting in the signs and symptoms of CHOPS syndrome.
cancers - associated with the AFF4 gene: The AFF4 gene is occasionally involved in chromosomal rearrangements (translocations) that are found in certain blood cancers called infant acute lymphoblastic leukemia and mixed lineage leukemia. The translocations fuse the AFF4 gene with another gene called MLL. An abnormal protein combining features of both the AFF4 and MLL proteins is produced from the combined gene. The abnormal protein likely disrupts the transcription elongation function of the SEC, which alters normal gene activity (expression) and results in the uncontrolled growth of cells that occurs in leukemia. Researchers are working to determine the specific effects of the abnormalities and how they lead to these particular cancers.

Where is the AFF4 gene located?

Cytogenetic Location: 5q31

Molecular Location on chromosome 5: base pairs 132,875,379 to 132,963,662

The AFF4 gene is located on the long (q) arm of chromosome 5 at position 31.

More precisely, the AFF4 gene is located from base pair 132,875,379 to base pair 132,963,662 on chromosome 5.

See How do geneticists indicate the location of a gene? in the Handbook.

Where can I find additional information about AFF4?

You and your healthcare professional may find the following resources about AFF4 helpful.

Educational resources - Information pages
Moecular Biology of the Cell (fourth edition, 2002): Transcription Elongation Produces Superhelical Tension in DNA

You may also be interested in these resources, which are designed for genetics professionals and researchers.

PubMed - Recent literature
OMIM - Genetic disorder catalog
Research Resources - Tools for researchers (3 links)

What other names do people use for the AFF4 gene or gene products?

AF4/FMR2 family member 4
AF5Q31
ALL1-fused gene from chromosome 5q31 protein
major CDK9 elongation factor-associated protein
MCEF

See How are genetic conditions and genes named? in the Handbook.

Where can I find general information about genes?

The Handbook provides basic information about genetics in clear language.

These links provide additional genetics resources that may be useful.

What glossary definitions help with understanding AFF4?

acids ; acute ; acute lymphoblastic leukemia ; chromosome ; congenital ; embryonic ; gene ;leukemia ; lineage ; protein ; pulmonary ; short stature ; stature ; syndrome ; transcription

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

References (8 links)

The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook