PLAAT4 and infection: MDA-5 is a Retinoic Acid Inducible Gene-1 (RIG-1)-like receptor coded by IFIH1 (interferon-induced helicase C domain-containing protein 1) gene that recognizes double-stranded (ds) RNA of viruses and induces a type I interferon response through various intermediaries.5 The exact pathogenesis is unknown; however, a role of infections and environmental factors superimposed on genetic susceptibility has been proposed.6