Seventeen-month old female GAA-KO mice were injected intravenously with AAV-LSPhGAApA and AAV-MHCK7hGAApA (n=4). (A) GAA activity in the indicated tissues. (B) Glycogen content for the mice shown in (A). (C) Vector genome quantification by Realtime PCR. Detection of the hGAA cDNA in GAA-KO mice following AAV-SPhGAApA administration at 3 months old (Young, n=4) or 12 months old (Old, n=4 for liver, n=2 for heart), or AAV-LSPhGAApA and AAV-MHCK7hGAApA co-administration at 17 months old (Very Old, n=4). Mean +/− s.d shown, and significant differences indicated by (*) indicating p < 0.05, (**) indicating p<0.01, and (***) indicating p<0.001 as calculated with an unpaired T-test.