Pediatric diffuse gliomas are currently subdivided into eight distinct types: four are low-grade and include diffuse astrocytoma, myeloblastosis gene (MYB) or MYB proto-oncogene like 1 (MYBL1)-altered; diffuse low-grade glioma, mitogen-activated protein kinase (MAPK) pathway-altered; angiocentric glioma; and polymorphous low-grade neuroepithelial tumor of the young (PLNTY). This evidence concerns the gene MYBL1 and polymorphous low grade neuroepithelial tumor of the young.