HES7 and spondylocostal dysostosis: Mutations in genes such as DLL3 (delta-like 3), MESP2 (mesoderm posterior bHLH transcription factor 2), LFNG (O-fucosylpeptide 3-beta-N-acetylglucosaminyl-transferase), HES7 (hes family bHLH transcription factor 7), and TBX6 (T-box 6) lead to the development of different types of SCDO (SCDO I, II, III, IV, V).