MESP2 and spondylocostal dysostosis: For example, frequently recessive mutations in DLL3, HES7, MESP2 and LFNG and a dominant mutation in TBX6 (Sparrow et al., 2013; Lefebvre et al., 2017) have been identified in patients with spondylocostal dysostosis (SCDO), which is characterized by severe vertebral malformations that include hemivertebrae, vertebral loss and fusion along the length of the axis (Takeda et al., 2018).