There are five RecQ helicases in human cells: RecQ-like helicase 1 (RECQL1), Werner syndrome RecQ-like helicase (WRN), Bloom syndrome RecQ-like helicase (BLM), RecQ-like helicase 4 (RECQL4) and RecQ-like helicase 5 (RECQL5) (9,10,12) Mutations in WRN, BLM and RECQL4 proteins can lead to genomic instability and predisposition to cancers, including colorectal, prostate and breast cancers (13–16). This evidence concerns the gene RECQL5 and Down syndrome.