Our genome sequencing of AO has confirmed the mutually exclusive mutational profile in IDHmut-1p/19q co-deleted and IDHmut non-1p/19q co-deleted tumour subtypes, which reflect distinct molecular mechanisms of oncogenesis—consistent with the requirement for either 1p/19q co-deletion or TP53 mutation post IDH mutation. The gene discussed is IDH2; the disease is neoplasm.