TWIST1 and craniosynostosis: RUNX2 protein function is repressed by TWIST1, mutations of which cause Saethre–Chotzen syndrome (OMIM 101400), a craniosynostosis syndrome characterized by coronal synostosis, facial asymmetry, ptosis small ears, and occasional syndactyly [el Ghouzzi et al., 1997; Howard et al., 1997; Krebs et al., 1997].