IDH3A and astrocytoma (excluding glioblastoma): Background: Glioblastoma (GBM) and grade 4 astrocytoma (ASTROG4) are aggressive primary brain tumors characterized by rapid growth, invasiveness, and poor prognosis, differentiated by the presence or absence of isocitrate dehydrogenase (IDH) mutation according to the World Health Organization (WHO) 2021 classification.