Molecular & Genetic Markers
ATRX loss
ATRX loss is the loss of a gene's normal function that, with an IDH mutation, helps identify an astrocytoma rather than an oligodendroglioma.
In short: ATRX loss
- It is the loss of normal ATRX gene function.
- It is detected by a tissue stain (immunohistochemistry).
- With an IDH mutation, it points to astrocytoma.
- It helps distinguish astrocytoma from oligodendroglioma.
What it is
ATRX loss refers to the loss of normal function of the ATRX gene in tumor cells, detectable by a tissue stain. In a diffuse glioma with an IDH mutation, ATRX loss helps identify the tumor as an astrocytoma rather than an oligodendroglioma.
Understanding ATRX loss
Among IDH-mutant diffuse gliomas, distinguishing astrocytoma from oligodendroglioma is important. ATRX loss is characteristic of IDH-mutant astrocytomas, while oligodendrogliomas typically retain ATRX (and instead have 1p/19q codeletion). So when a pathologist finds ATRX loss in an IDH-mutant glioma, it supports a diagnosis of astrocytoma. ATRX status is often assessed by immunohistochemistry (a stain that shows whether the normal protein is present), making it a practical, widely available marker. It works together with 1p/19q testing to separate the two IDH-mutant tumor types. Understanding ATRX loss clarifies a marker that helps distinguish astrocytoma from oligodendroglioma.
Why it matters
Understanding ATRX loss helps patients and families see one of the markers used to pin down the diagnosis — ATRX loss in an IDH-mutant glioma points to astrocytoma rather than oligodendroglioma.
Common questions
What is ATRX loss?
The loss of normal ATRX gene function in tumor cells.
What does it indicate?
With an IDH mutation, it points to astrocytoma.
How is it detected?
Often by a tissue stain (immunohistochemistry).
Bottom line
ATRX loss is the loss of normal ATRX function that, with an IDH mutation, helps identify an astrocytoma rather than an oligodendroglioma.
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