In human cells, the RecQ helicase family comprises five DNA helicases: RECQL1 (also known as RECQL or RECQ1), Bloom syndrome (BLM), Werner syndrome (WRN), Rothmund–Thomson syndrome (RTS; also known as RECQL4) and RECQL5 (Furuichi, 2001; Hickson, 2003; Shimamoto et al., 2004). The gene discussed is RECQL4; the disease is Werner syndrome.