Holt-Oram syndrome is caused by mutations in TBX5, a member of the Brachyury (T) gene family Li, Q.Y. et al. Nat. Genet. 15, 21–29 Mutations in human TBX5 cause limb and cardiac malformation in Holt-Oram syndrome Basson, C.T. et al. Nat. Genet. 15, 30–35