The original papers describing IDHmut gliomas were published in 2008 and 2009.1,2 Now, the classification of adult-type diffuse gliomas is based on the presence or absence of IDHmut (and 1p/19q codeletion).3 IDHmut, TERTwt, 1p/19q-intact gliomas are astrocytomas, and the vast majority of IDHmut astrocytomas contain mutations in TP53 and/or ATRX. The gene discussed is ATRX; the disease is glioma.