Gröbner et al. performed a WGS in 547 samples and a WES in 414 pediatric cancer samples (24 different histotypes), thus identifying a low overall incidence of single nucleotide variants (SNVs), with the exception of high-grade gliomas with line variants, biallelic germline in DNA repair genes, MSH6 (MutS Homolog 6) or PMS2 (PMS1 Homolog 2, Mismatch Repair System Component); these rare tumors harbored more than 10 mutations per megabase [12]. The gene discussed is PMS2; the disease is central nervous system cancer.