G4s can be unwound by specific helicases including werner syndrome RecQ like helicase (WRN), bloom syndrome, RecQ like helicase (BLM), FA complementation group J (FANCJ)/BRCA1 interacting DNA helicase 1 (BRIP1) and Petite Integration Factor 1 (PIF1) as reviewed in ref. 26. This evidence concerns the gene WRN and Bloom syndrome.