In 2016, the World Health Organization (WHO) updated the classification of CNS tumors, incorporating molecular biomarkers as part of the diagnosis of low-grade and high-grade gliomas, including mutations in the isocitrate dehydrogenase 1 and 2 genes (IDH) and the 1p/19q codeletion3. The gene discussed is IDH1; the disease is central nervous system neoplasm.