ACVR1 and malignant glioma: Key recent findings include recurrent mutations in the genes encoding histones 3.3 and 3.1 (H3F3A and HIST1H3B) as well as the activin A receptor type I (ACVR1) that are unique to paediatric high-grade glioma (pHGG) and diffuse intrinsic pontine glioma (DIPG) [18–20].