RECQL4 and Werner syndrome: These include Werner syndrome (WS), caused by loss-of-function mutations in the WRN gene and a primary focus for this perspective; a subset of Rothmund-Thomson syndrome caused by loss-of-function mutations in the RECQL4 gene [4,5]; and the recently identified RECON progeroid and genomic instability syndrome caused by biallelic loss-of-function mutations in the RECQL gene [6].