More specifically, haploinsufficiency of Twist1, using Twist1 (+/−) mouse mutants, results in coronal synostosis and in turn a widened skull in the left-right lateral direction with a shortening in its anterior-posterior length, similarly reflecting the phenotype of Saethre-Chotzen syndrome (Behr et al., 2011). This evidence concerns the gene TWIST1 and Saethre-Chotzen syndrome.