The most common low-grade glioma in children was pilocytic astrocytoma, belonging to the tumour type of circumscribed astrocytic gliomas, caused by extracellular-signal-regulated kinase (ERK) constitutive activation from its upstream BRAF mutations (BRAF-KIAA1549 fusion or BRAF-V600E) or NF1 alterations [63], and the less common active mutations of FGFR1 and PTPN11, and NTRK2 fusion [64]. The gene discussed is BRAF; the disease is pilocytic astrocytoma.