NIPBL and Roberts-SC phocomelia syndrome: SMC3 is acetylated by ESCO1 or ESCO2 (LOF mutations in which cause Roberts syndrome (MIM #268300)25) and deacetylated by HDAC8.11 There is growing evidence that NIPBL may regulate gene expression via cohesion-independent mechanisms.26, 27 It is not yet clear which cellular functions of NIPBL and the cohesin complex cause the clinical phenotype associated with each locus.