Though clinically distinct phenotypes are known to be encoded by different mutations in a single gene (Deng et al. 2010; Fecto et al. 2011), it is also possible that MDA5 is a monogenic lupus syndrome with a specific antibody rather than dermatomyositis since being clinically amyopathic is an essential feature of MDA5 or perhaps the MDA5 antibody is also present in SLE cohorts given the strong IFIH1 association. Here, IFIH1 is linked to dermatomyositis.