In the case of WRN helicase, chromosomal instability associated with increased somatic mutation, large DNA deletions (Fukuchi et al., 1989) and unusual dynamics in telomere shortening (Tahara et al., 1997; Sugimoto, 2014) have been found in cells from WS patients, suggesting that WRN may participate in the repair of DSB through HR and NHEJ repair pathways. Here, WRN is linked to Werner syndrome.