 Evidence of the presence of this additional regulatory element came from a group of patients that lacked a 20 kb region upstream of the β-globin cluster that was vital for expression of any of the β-globin genes.Even though all of the genes themselves and the other regulatory elements were intact, without this domain, none of the genes in the β-globin cluster were expressed.Although the name implies that the LCR is limited to a single region, this implication only applies to the β-globin LCR (HBB-LCR).