IDH1 and glioma: Various studies have reported spontaneous mutations in the NADP+-dependent IDH1 gene in glioma along with mutation in the IDH2 gene which is located on 15q26.1 chromosomal position with a frequent mutation at R172K (sometimes also at R172K, R172W, and R172M) of R172 (Horbinski, 2013; Yan et al., 2009).