AFF2 Gene
AF4/FMR2 Family Member 2
Gene Information Card
| Symbol | AFF2 |
|---|---|
| Full Name | AF4/FMR2 Family Member 2 |
| Gene Type | Protein coding |
| Chromosomal Location | Xq28 |
| NCBI Gene ID | 2335 ncbi.nlm.nih.gov/gene/2335 |
| Ensembl ID | ENSG00000102316 |
| UniProt ID | P51816 |
| OMIM ID | 300806 |
| HGNC ID | 325 |
| Aliases | FMR2, FRAXE, MRX2, OX19 |
Description
The AFF2 gene (AF4/FMR2 Family Member 2) is located on the X chromosome at Xq28. It encodes a nuclear protein involved in transcriptional regulation, particularly as a component of the super elongation complex (SEC). Mutations and expansions of a CCG repeat in the 5' untranslated region of AFF2 are associated with FRAXE intellectual disability syndrome. The gene is widely expressed, with highest levels in the brain, placenta, and lymphoid tissues.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| FRAXE intellectual disability syndrome | Expansion of a CCG trinucleotide repeat in the 5' UTR leads to hypermethylation and transcriptional silencing of AFF2, resulting in loss of function. | OMIM #309548; ClinVar; multiple peer-reviewed studies |
| Autism spectrum disorder (susceptibility) | Rare variants and deletions in AFF2 have been identified in individuals with ASD, suggesting a contributory role. | ClinVar; literature reports |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain | 12.5 | Medium |
| Placenta | 8.3 | Medium |
| Lymph node | 6.1 | Low |
| Testis | 4.7 | Low |
| Heart | 3.2 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| SH-SY5Y (neuroblastoma) | 15.2 | Neuronal model |
| HEK293 (embryonic kidney) | 9.8 | Common expression system |
| K562 (lymphoblast) | 7.4 | Lymphoid origin |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| CCG repeat expansion (>200 repeats) | Trinucleotide repeat expansion | Rare (estimated 1 in 50,000 males) | Loss of function via promoter hypermethylation and gene silencing |
| c.1234C>T (p.Arg412*) | Nonsense | Very rare | Premature stop codon, loss of function |
Mutation functional classification
Loss of Function (LOF)
CCG repeat expansions and nonsense mutations cause loss of AFF2 protein function, leading to FRAXE intellectual disability.
Gain of Function (GOF)
No evidence of gain-of-function mutations in AFF2.
Dominant Negative (DN)
No evidence of dominant-negative mutations in AFF2.
View complete mutation data：
Gene Ontology (GO)
| • GO:0005515 - protein binding | • GO:0005634 - nucleus |
| • GO:0006357 - regulation of transcription by RNA polymerase II | • GO:0008270 - zinc ion binding |
Pathways
• Super elongation complex (SEC)
• Transcriptional regulation by RNA polymerase II
Protein Summary
The AFF2 protein (also known as FMR2) is a nuclear phosphoprotein of approximately 1311 amino acids. It contains a conserved N-terminal homology domain and a C-terminal transcriptional activation domain. AFF2 is a component of the super elongation complex (SEC), which facilitates transcriptional elongation by RNA polymerase II. The protein is highly expressed in the brain and is essential for normal cognitive development. Loss of AFF2 function due to repeat expansions or mutations leads to FRAXE intellectual disability syndrome.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| AFF2 Knockout HEK293 Cell Line | EDJ-KQ4619 | Human | 2334 | Details Get a Quote |
| AFF2 Knockout HeLa Cell Line | EDJ-KQ53258 | Human | 2334 | Details Get a Quote |
| AFF2 Knockout A-549 Cell Line | EDJ-KQ61741 | Human | 2334 | Details Get a Quote |
| AFF2 Knockout HCT 116 Cell Line | EDJ-KQ70227 | Human | 2334 | Details Get a Quote |
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