In one series of n = 13 grade III-IV SCA, 0 out of 13 tested had BRAF V600E mutation or IDH1 mutation at immunohistochemistry (IHC); 3/10 tested had TERT promotor mutation, 1/10 EGFR mutation, 8/10 TP 53 mutation and 6/13 H3K27M mutation, all mutations detected by Next Generation Sequencing (NGS). The gene discussed is IDH1; the disease is autosomal dominant cerebellar ataxia.