The transcription regulatory role may be especially relevant given that mutation in human cohesin subunits (SMC1A/Smc1, SMC3, RAD21/Mcd1/Scc1) and cohesin-regulatory factors (ESCO2/Eco1/Ctf7, HDAC8/Hos1, NPBL/Scc2, APRIN/Pds5, ChlR1/DDX11/Chl1 and BACH1/BRIP/FANCJ/Chl1) result in severe developmental maladies that include Cornelia de Lange Syndrome, Roberts Syndrome, Warsaw Breakage Syndrome and Fanconi Anemia [5-17]. Here, RAD21 is linked to Warsaw breakage syndrome.