Isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) are key metabolic enzymes that convert isocitrate to alpha-ketoglutarate. Mutations in the IDH1 and IDH2 genes are common genetic alterations found in gliomas, which are a type of brain tumor that originates from glial cells. These mutations result in the conversion of alpha-ketoglutarate to 2-hydroxyglutarate, which functions as an oncometabolite and is a key driver of gliomagenesis. IDH1 and IDH2 mutations are particularly prevalent in lower-grade gliomas, including diffuse and anaplastic astrocytomas and oligodendrogliomas, as well as in secondary glioblastomas, which develop from lower-grade gliomas.

Glioma-specific mutations in IDH1 are known to most frequently affect codon 132 resulting in an amino acid substitution from arginine to histidine (R132H). This mutation is frequently found in gliomas and is associated with a better prognosis. Mutations in the IDH2 gene occur less frequently than IDH1 mutations. The IDH2 mutations typically affects the codon R172 and often leads to an amino acid change from arginine to leucine (R172L). Detecting the presence of IDH1 and IDH2 mutations in gliomas is crucial for determining the prognosis, treatment options, and overall management of patients with these tumors.