The antagonistic reaction, the stimulation of GTP hydrolysis by RAS-GAPs such as neurofibromin 1 (NF1), is of particular interest from the pLGG perspective, as this tumor suppressor product is often lost or inactive in optic pathway glioma (OPG), which often occur in patients suffering from the RASopathy neurofibromatosis I (15% of all pLGG) [7, 13]. The gene discussed is NF1; the disease is optic pathway glioma.