AbstractChordoid glioma (ChG) is a characteristic, slow growing, and well-circumscribed diencephalic tumor, whose mutational landscape is unknown. Here we report the analysis of 16 ChG by whole-exome and RNA-sequencing. We found that 15 ChG harbor the same PRKCA ^D463H mutation. PRKCA encodes the Protein kinase C (PKC) isozyme alpha (PKCα) and is mutated in a wide range of human cancers. However the hot spot PRKCA ^D463H mutation was not described in other tumors. PRKCA ^D463H is strongly associated with the activation of protein translation initiation (EIF2) pathway. PKCα^D463H mRNA levels are more abundant than wild-type PKCα transcripts, while PKCα^D463H is less stable than the PCKα^WT protein. Compared to PCKα^WT, the PKCα^D463H protein is depleted from the cell membrane. The PKCα^D463H mutant enhances proliferation of astrocytes and tanycytes, the cells of origin of ChG. In conclusion, our study identifies the hallmark mutation for chordoid gliomas and provides mechanistic insights on ChG oncogenesis.