IDH1 and central nervous system cancer: The first subtype is named G-CIMP (Glioma CpG island methylator phenotype), characterized by mutations in genes such as IDH1/2, TP53, and ATRX. The second subtype is named IDH mutant-codel, characterized by mutations in genes such as IDH1/2, CIC, and FUBP1, along with a chromosomal codeletion of 1p/19q.