We also showed in supratentorial pediatric GBM that H3.3 mutations significantly overlapped with mutations in TP53 and ATRX (alpha-thalassemia/mental-retardation syndrome-X-linked) [23], which encodes a subunit of a chromatin remodelling complex required for H3.3 incorporation at pericentric heterochromatin and telomeres [7, 12]. This evidence concerns the gene ATRX and glioblastoma.