Gliomas are the most common primary central nervous system (CNS) neoplasms in 
children and adolescents and are thought to arise from their glial progenitors 
or stem cells. Although the exact cells of origin for most pediatric gliomas 
remain to be identified, our current understanding is that specific cell 
populations during CNS development are susceptible to particular oncogenic 
events during certain time windows and thus give rise to pediatric gliomas with 
distinct histological, molecular, and clinical features. These may be roughly 
segregated into low-grade gliomas (WHO grades I or II; including most mixed 
glial-neuronal tumors) and high-grade gliomas (WHO grades III or IV) according 
to their clinical course when untreated, even though this is not yet entirely 
clear for some of the recently emerging groups. The genetic and epigenetic 
characterization of pediatric gliomas across ages and histologies has 
facilitated the delineation of biologically relevant subgroups and have revealed 
potentially targetable alterations in some of them. This review outlines 
diagnostic features and molecular alterations in pediatric low- and high-grade 
gliomas and how the latter might be exploited with future targeted therapeutic 
strategies.