Q (sonnet): what do idh1 mutations do?

═ answer (success)
IDH1 (isocitrate dehydrogenase 1) mutations are recurrent, well-characterized alterations found across several cancer types, most notably lower-grade gliomas and acute myeloid leukemia (AML), and also in cholangiocarcinoma and chondrosarcoma.

**Functional consequence:** The vast majority of IDH1 mutations are heterozygous missense changes at a single hotspot residue, **R132** (e.g., R132H, R132C, R132S). This is a gain-of-function/neomorphic mutation:
- Wild-type IDH1 normally converts isocitrate to α-ketoglutarate (α-KG) in the cytoplasm as part of normal metabolism.
- Mutant IDH1 acquires a new enzymatic activity that instead converts α-KG to **2-hydroxyglutarate (2-HG)**, an "oncometabolite."
- 2-HG accumulates to high levels and competitively inhibits α-KG-dependent dioxygenases, including TET2 (DNA demethylation) and histone demethylases (e.g., KDM enzymes).
- This leads to widespread **DNA and histone hypermethylation**, blocking normal cellular differentiation — contributing to gliomagenesis and leukemogenesis.

In gliomas, IDH1 mutation status is a key diagnostic and prognostic marker (IDH-mutant gliomas generally have better prognosis than IDH-wildtype). In AML, IDH1 mutations are targetable — the mutant enzyme is the basis for FDA-approved inhibitors (e.g., ivosidenib).

I did not query mutation-specific driver/oncogenicity annotations from the database for this answer — this is general molecular biology background, not a specific cBioPortal query result.

Would you like me to pull up IDH1 mutation frequency and hotspot distribution (e.g., R132H proportion) across specific studies, such as glioma or AML cohorts, in cBioPortal?