In 2011, mutations in the ATRX gene were described for the first time in a small fraction of adult and pediatric glioblastomas (GBM), as well as oligodendrogliomas (OG), and a significant correlation with alternative lengthening of telomeres (ALT), a presumed precursor to genomic instability, was demonstrated [3]. Here, ATRX is linked to glioblastoma.