We here compare the whole genome methylation and expression patterns of the healthy brain with that of LGG taken from our previous studies using the classification of LGG into six methylation subtypes M1–M6 of different characteristics including glioblastoma (GBM)-like IDH-wt (M1), IDH-mut astrocytoma-like (IDH-A, M2–M4) and oligodendroglioma-like (IDH-O, M5) as well as neuronal (NL, M6) tumors (Figure 8; for the gene expression analysis see Figure A8) [20,21]. The gene discussed is IDH1; the disease is oligodendroglioma.