Specifically, the genomic difference between glioblastoma and IDH1/2-mutant astrocytoma (median JD: 0.147) was significantly higher than the genomic heterogeneity within glioblastoma (median JD: 0.088, P < .001) or IDH1/2-mutant astrocytoma (median JD: 0.059, P < .001). The gene discussed is IDH1; the disease is astrocytoma (excluding glioblastoma).