Saethre-Chotzen syndrome is a common autosomal dominant form of 
craniosynostosis, the premature fusion of the sutures of the calvarial bones of 
the skull. Most Saethre-Chotzen syndrome cases are caused by haploinsufficiency 
for the TWIST gene. Mice heterozygous for a null mutation of the Twist gene 
replicate certain features of Saethre-Chotzen syndrome, but have not been 
reported to exhibit craniosynostosis. We demonstrate that Twist heterozygous 
mice exhibit fusions of the coronal suture and other cranial suture 
abnormalities, indicating that Twist heterozygous mice constitute a better 
animal model for Saethre-Chotzen syndrome than was previously appreciated.