Both the ATR and FA pathways, together with proteins such as Rad51, Rad52, the endonucleases ERCC1 and MUS81, the BLM (Bloom syndrome protein) helicase, and DNA polymerases, constitute part of a still growing network of proteins responsible for the maintenance of genomic stability at the CFS loci. This evidence concerns the gene BLM and myalgic encephalomeyelitis/chronic fatigue syndrome.