DDX17 and myotonic dystrophy type 1: Aside from the MBNL proteins (and likely CUG-BP1) (11,48,62) DEAD-box helicases DDX5, DDX17 and DDX6, which are proteins with general mRNP remodeling capacity, have recently been shown to modulate CUG-expanded foci and may play a role in DM1 pathogenesis (46,47).