Previous investigations of the frequencies of molecular and genetic alterations in low-grade gliomas disclosed IDH mutations in as many as 85% [14], 1p19q codeletion in up to 80% of O [26], and ATRX loss as high as 70% to 72% in IDH mut-noncodel tumors [12, 18]. The gene discussed is ATRX; the disease is glioma.