Individual driver variants can be found in the lists of mutations provided in Supplementary Tables 10 – 14 . A single asterisk indicates that the identification of the LOH event was only possible because we could phase parental alleles ( Methods ). The low cell fraction of many of these meant that it was not possible to determine the breakpoint. When counting LOH events, those called from sequences derived from the same original bulk biopsy are treated as the same event, and those from different biopsies are treated as unique. These events should not be considered when comparing mutations against the other two children because their SNP alleles on chromosome 17 could not be phased. Double asterisks indicate that in sequences from the high-grade glioma, we only considered mutations in genes recognized in a large meta-analysis to be drivers of these neoplasms ( Methods ). Triple asterisks indicate that one additional MSH6 frameshift mutation (p.F1088fs*2) was noted in the spinal cord (PD51122v_lo0008) and spleen (PD51122z_lo0017) of the child with neurofibromatosis type 1; this, however, remained heterozygous without evidence of hypermutation and did not co-occur with somatic NF1 mutation, making it of uncertain significance. Four asterisks indicate that chromosome 11p LOH was identified in a single sample after manual inspection of the copy number output, although it was too low a fraction to be detected by the copy number caller. Del, deletion; Inv, inversion.
