We then evaluated rare exonic variants in known cancer predisposition genes10 or previously reported chordoma-related genes (including potential germline susceptibility and somatically mutated genes, Supplementary Table 1) and found two variants, each in a single patient, that were classified as pathogenic (ERCC5, c.697 C > T, p.Gln233*) or likely pathogenic (LP) (BLM, c.3564delC, p.Phe1189fs) (see classification criteria in “Methods”). This evidence concerns the gene BLM and chordoma.