IDH1 and Guillain-Barre syndrome: In the most recent 5th edition of the WHO classification of the CNS tumors, the term “multiforme” was excluded and GBs are further designated as diffuse astrocytic tumors in adults that do not harbor isocitrate dehydrogenase (IDH) mutation (IDH-wild type) but present one of the following characteristics: presence of necrosis or/and microvascular proliferation, telomerase reverse transcriptase (TERT) promoter mutation, and Epidermal Growth Factor Receptor (EGFR) gene amplification, as well as combined gain of whole chromosome 7 and loss of chromosome 10 [+7/−10] [4].