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The official name of this gene is “AF4/FMR2 family, member 2.”
AFF2 is the gene's official symbol. The AFF2 gene is also known by other names, listed below.
The AFF2 gene provides instructions for making a protein that is found in the nucleus of cells but whose function is not well understood. Some studies suggest that it acts as a transcription factor, which means that it attaches (binds) to specific regions of DNA and helps control the activity of other genes, although the identity of these genes is unknown. Other studies show that the protein can attach to specific regions of messenger RNA (mRNA), which is a chemical cousin of DNA that serves as the genetic blueprint for protein production. It is thought that the AFF2 protein helps control the process by which the mRNA blueprint is cut and rearranged to produce different versions of proteins (alternative splicing).
One region of the AFF2 gene contains a particular DNA segment known as a CCG trinucleotide repeat, so called because this segment of three DNA building blocks (nucleotides) is repeated multiple times within the gene. In most people, the number of CCG repeats ranges from 4 to about 40.
Mutations in the AFF2 gene cause fragile XE syndrome, a condition characterized by mild intellectual disability and learning difficulties. Nearly all cases are caused by a mutation called a CCG trinucleotide repeat expansion, in which the CCG trinucleotide is abnormally repeated more than 200 times, which makes this region of the gene unstable. As a result, the AFF2 gene is turned off (silenced), and no protein is produced from it. It is unclear how a shortage of this protein leads to problems with intellectual functioning.
Rarely, small deletions of genetic material from the AFF2 gene are associated with fragile XE syndrome, although how these deletions affect the protein and lead to intellectual disability is unknown.
Cytogenetic Location: Xq28
Molecular Location on the X chromosome: base pairs 148,500,618 to 149,000,662
The AFF2 gene is located on the long (q) arm of the X chromosome at position 28.
More precisely, the AFF2 gene is located from base pair 148,500,618 to base pair 149,000,662 on the X chromosome.
See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.
You and your healthcare professional may find the following resources about AFF2 helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.
alternative splicing ; disability ; DNA ; gene ; mental retardation ; messenger RNA ; mRNA ; mutation ; nucleus ; protein ; RNA ; splicing ; syndrome ; transcription ; transcription factor ; trinucleotide repeat
You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).
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? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.