MOBP and neoplasm: Gene expression differences between the various ACVR1 mutations revealed an upregulation of genes involved in oligodendrocyte differentiation in G328E/V/W mutant tumours compared to R206H and G356D, including MOG (myelin oligodendrocyte glycoprotein), MAG (myelin-associated glycoprotein), MBP (myelin basic protein 1) and MOBP (myelin-associated oligodendrocyte basic protein) (Supplementary Fig. 1e, f).