As in GCTB, histone mutations have been characterized as driver events chondroblastoma: 96% of cases harbor p.Lys36Met (p.K36M) mutations, most commonly in H3-3B (H3F3B), but rarely in the paralogous gene H3-3A (H3F3A) [80]. The gene discussed is H3-3A; the disease is chondroblastoma.