Cohesinopathies are genetic diseases caused by mutations in genes involved in the sister chromatid cohesion process, including: Cornelia de Lange syndrome (CdLS), caused by mutations in genes encoding the cohesin structural components (SMC1A, SMC3 and RAD21) and regulators (NIPBL and HDAC8); Roberts syndrome (RBS), due to mutations of the cohesin acetyl-transferase gene (ESCO2) and chronic atrial and intestinal dysrhythmia (CAID) syndrome, linked to mutations of the SGOL1 gene encoding Shugoshin [68,69]. The gene discussed is RAD21; the disease is Roberts-SC phocomelia syndrome.