IDH1, also named as PICD and IDP, belongs to the isocitrate and isopropylmalate dehydrogenases family. It is a common feature of a major subset of primary human brain cancers. It can form a homodimer(PMID:15173171).IDH1 mutation is always heterozygotic and IDH1 functions as a dimer, theoretically there will be 25% each wild type and mutant homo-dimers and 50% hetero-dimers present in the tumor cells(PMID:21079649 ).