HES7 is a 225 amino acid transcriptional repressor protein. Localized to the nucleus, HES7 represses transcription of N box- and E box-containing promoters. HES7, along with family member HES1, is thought to cooperatively regulate somite formation in the presomitic mesoderm. HES7 may also be essential for coordinated somite segmentation by acting as a segmentation clock. HES7 contains one basic helix-loop-helix (bHLH) domain and one Orange domain. Mutations in HES7 have been found to cause spondylocostal dysostosis, an autosomal recessive disorder characterized by deformities of the chest and spine.