PIGG and infection: The nonfunctional c.1574C[7]/1657G Variant 1 encodes a nonfunctional Mga-M protein fusion protein with a 62-aa bridge encoded by the intergenic sequence between the mga and emm genes, the functional c.1574C[6]/1657G variant has 543 amino acid residues and is similar with the c.1571C[6] mga variants of MGAS2221 that were from the c.1574C[7] mga variant of MGAS2221 in mouse infection; and the G-to-A nonsense mutation at base 1657 of the c.1574C[7] mga variant converts Variant 1 into c.1574C[7]/1657A Mga variant that is 21 aa-residue longer than the wt Mga protein (Figure 4B) (Table 4).