The higher rate of near-mortality observed in mice infected with strain M4-LC-1 despite the absence of capsule is likely due to the large number of virulence factor encoding genes whose transcript levels were increased including emm, prtS, scpA, and slo. Additionally, the upregulation of genes from the FCT locus presumably would result in increased pilus production, but pilus production can either increase or decrease GAS virulence depending on strain and infection site [66–68]. The gene discussed is ARX; the disease is infection.