“…A link to the chromosome 7q33 region was demonstrated in families with a high incidence of chordomas, particularly those of the skull base. In this study, chondroid chordoma showed a normal karyotype, whereas in conventional chordoma, there were complex numerical and structural aberrations involving chromosomes 1, 2, 3, 5, 8,9,11,15,19,20, and X. Dedifferentiated chordomas were polyploid with a complex karyotype of 71 to 123 chromosomes. [337][338][339] Gil and colleagues 340 recently reported cytogenetic differences between three histologic variants of clival chordoma.…”