IFIH1 and Smith-Magenis syndrome: In the case of MDA5, a missense mutation in the IFIH1 gene (c.2465G>A; p.Arg822Gln) has been identified as the cause of classical SMS, characterized by dental anomalies, aortic and valvular calcification, glaucoma, and an enhanced type I IFN signature gene expression pattern (Rutsch et al., 2015).