TOP3A and Bloom syndrome: These are RAD54, MRE11, SMC1, TOP3, RECQ4A, and ESP. That these genes are truly fundamental in genome maintenance is also underlined by the fact that all of them have been implicated in numerous human diseases associated with genome instability, including cancer, Ataxia-Telangiectasia-like disorders, Bloom Syndrome and others, e.g. [45]–[50].