 Isocitrate deyhydrogenases IDH1 and IDH2 are catalysts responsible for the conversion of isocitrate to 2-oxoglutarate.The isocitrate deyhydrogenases IDH1 and IDH2 mutations disrupt this process resulting in unregulated production of α-ketoglutarate and a reduction in chondrocyte proliferation.In many cases of cartilaginous tumors, IDH1 and IDH2 point mutations were found thus explaining why Ollier disease is associated with many different associated conditions.