TSC1 and Inherited cancer-predisposing syndrome: Most chordomas are sporadic, but a small percentage of cases are due to hereditary cancer syndromes (HCS) such as tuberous sclerosis 1 and 2 (TSC1/2), or constitutional variants in the gene encoding brachyury T (TBXT) (Pillay et al., Nat Genet 44:1185–1187, 2012; Yang et al., Nat Genet 41:1176–1178, 2009).