The RTEL1 helicase, mutated in Dyskeratosis congenita (DC) or its more severe form Hoyeraal-Hreidarsson syndrome (HHS), and the DDX11 helicase mutated in Warsaw Breakage syndrome (WBS) have most recently joined the group of clinically relevant Fe-S DNA helicases. Here, DDX11 is linked to dyskeratosis congenita.