This study was unable toidentify any somatic mutations, tumour associated polymorphisms or epigeneticsilencing of D2HGDH or L2HGDH [57] in patientslacking IDH1 or IDH2 mutations [57].Originally identified as somatic mutations, a separate study has detectedheterozygous germline mutations in IDH2 that alter enzyme residue R140 in 15unrelated patients with d-2-hydroxyglutaric aciduria. The gene discussed is IDH1; the disease is neoplasm.