ATRX mutation / ATRX loss (IHC)
Deterministic view of the source YAML entity. Clinical authority remains with the cited source IDs and reviewer sign-off state.
| ID | BIO-ATRX-MUTATION |
|---|---|
| Type | Biomarker |
| Aliases | ATRX IHC lossATRX inactivationATRX loss of expressionATRX nullalpha-thalassemia mental retardation X-linked mutation |
| Status | reviewed 2026-05-05 | pending_clinical_signoff |
| Diseases | None declared |
| Sources | SRC-NCCN-CNS-2025 |
Biomarker Facts
| Biomarker type | gene_mutation |
|---|---|
| Mutation details | {"gene_id_ncbi": 546, "gene_symbol": "ATRX", "note": "ATRX (chromatin remodeling helicase) loss-of-function mutations are found in ~70-80% of IDH-mutant astrocytomas (grade 2-4) and are characteristic of the astrocytoma lineage. ATRX mutations are MUTUALLY EXCLUSIVE with 1p/19q codeletion — ATRX loss defines astrocytoma, while 1p/19q codeletion defines oligodendroglioma. ATRX mutations correlate with Alternative Lengthening of Telomeres (ALT) mechanism. IHC (loss of nuclear ATRX expression) is... |
| Measurement | MethodIHC on FFPE brain tumor tissue (ATRX antibody, rabbit anti-ATRX e.g. Sigma HPA001906). Loss of nuclear staining in tumor cells with retained expression in stromal cells / endothelium (internal positive control) = ATRX loss (abnormal). Preserved nuclear staining = ATRX intact (normal). IMPORTANT: endothelial cells / neurons must show positive staining to interpret tumor ATRX loss as true loss vs technical failure. NGS panel: recommended when IHC is equivocal or when comprehensive molecular profiling is performed. |
| Related biomarkers | BIO-IDH1-R132H BIO-IDH-MUTATION BIO-1P19Q-CODELETION BIO-TP53-IHC BIO-TERT BIO-CDKN2A |
Notes
WHO CNS 5th edition (2021) uses ATRX as a key classifier for adult diffuse gliomas. Clinical impact: astrocytoma has worse prognosis than oligodendroglioma (IDH-mut/1p19q-codel) but better than GBM (IDH-wildtype). For grade 3 astrocytoma: RT + TMZ is standard (RTOG 9813 / analogous to CATNON for grade 3). For grade 4 astrocytoma IDH-mutant (formerly "secondary GBM"): Stupp + RT is standard (same as IDH-wildtype GBM, though prognosis better). ATRX loss associates with ALT telomere lengthening — potential future therapeutic target.
Used By
Biomarker
BIO-1P19Q-CODELETION- 1p/19q codeletion