There are a number of genomic alterations associated with glioblastoma, the most commonly described being isocitrate dehydrogenase (IDH), fibroblast growth factor receptor (FGFR), a-thalassemia/mental-retardation-syndrome-X-linked (ATRX), and tumor protein P53 (TP53) gene mutations, epidermal growth factor receptor (EGFR) gene amplification, loss of heterozygosity of the phosphatase and tensin homolog (PTEN) gene and telomerase reverse transcriptase (TERT) promoter mutation [47,49,54,55]. The gene discussed is PTEN; the disease is thalassemia.