It has been suggested recently that the IFIT family proteins ISG56/IFIT1 and ISG54/IFIT2 can recognize and inhibit the translation of (viral) mRNA caps that are not 2′-O-methylated and that this can act as a mechanism by which the host cell can distinguish self from non-self mRNA during virus infection (Daffis et al., 2010). The gene discussed is IFIT1; the disease is viral infectious disease.