IDH2 and myelodysplastic syndrome: In conclusion, the study of IDH mutations in MDS show several relevant findings, supporting a pathogenic role: IDH mutations are present in MDS at a frequency lower than that observed in AML; the frequency of IDH1/IDH2 mutations increases from lower-risk to higher-risk MDS, thus suggesting a role in clinical progression; in a fraction of MDS, IDH2, and IDH1 mutations are involved in the ancestral neoplastic clone.