This phenotype could again be rescued by expression of WT TOP3A (Fig 3F, lane 5) but only partially rescued by the expression of several pathological variants, including Arg103Gln, Arg558Trp, Met575Val and the Bloom syndrome‐associated variants Ala176Val and Ser810* (Fig 3F, lanes 6–13). Here, TOP3A is linked to Bloom syndrome.