Treacher Collins syndrome (TCS) is an autosomal dominant disorder of craniofacial development which results from loss-of-function mutations in the gene TCOF1. TCOF1 encodes the nucleolar phosphoprotein, Treacle, which plays a key role in pre-ribosomal processing and ribosomal biogenesis. In mice, haploinsufficiency of Tcof1 results in a depletion of neural crest cell precursors through high levels of cell death in the neuroepithelium, which results in a reduced number of neural crest cells migrating into the developing craniofacial complex. These combined advances have already impacted on clinical practice and provide invaluable resources for the continued dissection of the developmental basis of TCS.