EIF2AK2 and myotonic dystrophy type 1: Taken together, we concluded that the reduction in foci mediated by C16 PKRi was likely not related to toxicity, although the only foci disrupting concentration of 10μM observed in our DM1 fibroblast model is both a significant excess of PKR inhibiting concentrations (IC50 0.21uM [28]) as well as ultimately cytotoxic at a later time-point.