Immunohistochemistry results showed positive glial fibrillary acidic protein (GFAP) (present), variable oligodendrocyte transcription factor 2 (OLIG2), alpha thalassemia/mental retardation syndrome X-linked gene (ATRX) (interpreted as retained-wildtype), IDH1-R123H mutation (absent), p53 (increased expression >10% of lesional cells suggesting mutation), Ki67 (highly variable but focally up to 40%), MLH1/MSH2, MSH6, and PMS2 (all somehow variable, interpreted as retained). The gene discussed is GFAP; the disease is alpha thalassemia spectrum.