IDH2 and Cowden syndrome 1: Profiling a total of 350 CS cases for IDH1 and IDH2, using ddPCR (n = 282) and WGS (n = 68), we verified previous findings that IDH2 are less frequent than IDH1 mutations (IDH1: 51%, IDH2: 14%, IDHwt: 35%) [16, 26, 41].