WRN and Werner syndrome: Therefore, mutations in three of the RecQ family members, namely, BLM, WRN, and RECQL4, lead to Bloom syndrome (BS), Werner syndrome (WS), and Rothmund–Thomson syndrome (RTS), respectively, in humans, whereas in yeast, lack of the Sgs1 induces a hyper-recombination as well as hypersensitivity to a wide range of DNA-damaging agents (Watt et al., 1996).