TWIST1 and craniosynostosis: Several rare disorders have been shown to be caused by mutations in TWIST1: Saethre-Chotzen (SCS) [18], Robinow-Sorauf (RSS) [19] and Sweeney-Cox (SwCS) syndromes [20] and Craniosynostosis-1 (CRS1) [21], all presenting with craniosynostosis.