These include mutations in CTNNB1 (= beta-Catenin) in desmoid-type fibromatosis, H3-3A in conventional giant cell tumor of bone, H3-3B in chondroblastoma, IDH1/2 in cartilage tumors, KRAS and FGFR1 in non-ossifying fibroma, and GNAS in fibrous dysplasia amongst others. The gene discussed is IDH1; the disease is chondroblastoma.