QTRT1 and multiple sclerosis: Of note, queuosine hypomodification has been reported in several cancers and in multiple sclerosis via reduced activity of tRNA guanine transglycosylase (TRT) or via promoter methylation of the genes coding for the TRT subunits (QTRT1 and QTRT2) (Baranowski et al., 1994; Pathak et al., 2005; Varghese et al., 2017; Hayes et al., 2020).