1. Roberts Supplemental Figure 1 Plethysmography Mouse Count fTVbMVbPenhPAURpefCompPIFbPEFbTiTeEF50TrTbodyTcRHRinx 4 Weeks WT D24Average430.2740.14663.3710.3990.7750.48710.4044.8882.2990.0520.0990.1910.05837.524.77420.73750.351 SEM13.7250.0085.3080.0110.0130.0120.1010.3530.1790.0010.0040.0160.00200.2620.2242.679 Sgcg -/- D29Average418.1600.12853.3230.4880.8110.48310.7383.9222.0730.0580.0980.1690.05737.524.06441.25647.356 SEM15.2920.0043.4370.0370.0380.0240.1480.2240.1200.0020.0040.0100.00200.2918.0962.813 Mdx10Average443.7540.16372.9680.4320.8520.41810.2645.7082.6950.0480.1010.2020.05837.523.04538.82463.584 SEM4.8210.0021.4750.0060.0080.0040.0090.0890.0720.0000.0030.0080.00200.0550.2353.156 8 Weeks WT D26Average414.2160.17974.0180.5380.8520.44310.6435.3643.0070.0560.1000.2350.05737.524.02537.13143.797 SEM13.1460.0085.1990.0690.0470.0340.2700.2930.2760.0020.0050.0200.00300.0418.8544.250 Sgcg -/- D29Average376.0020.16059.0560.5690.8820.43310.4454.4322.4180.0620.1110.1880.06337.523.42438.93540.369 SEM8.3270.0052.4640.0400.0190.0150.1980.2080.0960.0020.0030.0070.00200.1936.7811.228 Mdx20Average414.8700.255106.1170.9091.1850.27611.1637.5245.0310.0580.1070.3440.05237.523.42062.71941.596 SEM26.7960.0159.5810.1310.1020.0280.1650.4560.5590.0060.0140.0420.00500.2471.2247.381 12 Weeks WT D20AverageN/A SEMN/A Sgcg -/- D27Average395.6700.17970.1450.4930.8210.46710.1285.2322.7710.0590.1090.2260.06337.523.52927.24445.422 SEM13.3470.0052.8780.0360.0380.0290.0430.2160.0970.0020.0040.0090.00200.2933.0802.705 Mdx10Average423.5600.286119.3500.9161.1250.25511.6538.1665.7400.0560.0950.3680.04837.524.22564.53039.630 SEM9.6770.0145.2220.0600.0280.0070.1090.2810.3190.002 0.0230.00100.2040.1852.907 16 Weeks WT D24Average380.5860.18971.1510.5400.8860.43310.1935.2842.8790.0610.1120.2310.06337.523.85325.12243.694 SEM6.8750.0115.6720.0180.0280.0180.0460.2970.2260.0010.0030.0200.00200.0710.8130.935 Sgcg -/- D26Average350.7720.19064.5710.5490.8900.41910.1834.9132.5940.0660.1220.2040.06837.523.96423.36038.035 SEM7.4990.0092.5510.0260.0310.0210.0430.1730.0940.0020.0040.0070.00200.1441.2811.738 Mdx8Average407.6130.284114.2460.9041.1060.27011.1657.8855.4180.0580.0990.3670.05137.523.40463.00737.073 SEM7.8700.0073.4690.0460.0320.0100.0690.1710.2060.0010.0030.0160.00200.1430.3251.798

2. Morphological Parameters Mouse Count LVAWd (mm) LVAWs (mm) LVPWd (mm) LVPWs (mm) LVIDd (mm) LVIDs (mm)RWT LV mass (mg) Mouse Wt (g) Diastolic Parameters E (mm/ sec) A (mm/ sec)E/A E DT (msec) IVRT (msec) E' (mm/ sec) A' (mm/ sec)E'/A'E/E'EDV (uL) Systolic Parameters EF (%)FS (%)ESV (uL) SV (  L) CO (mL/min)HR S' (mm/ sec)PA VTIPA ETPA ATPA AT/ET 4 Week WT D20AverageN/A WT D2AverageN/A WT D2AverageN/A SEMN/A SEMN/A SEMN/A Sgcg -/- D28Average0.6341.0080.7251.1332.9761.8160.46448.81010.450KO D2Average676.345434.1351.63318.71112.07924.13624.4011.10929.98034.795KO D2Average70.64039.31510.37124.42411.631477.23623.52726.39149.44015.7610.317 SEM0.0360.0560.0460.0760.1270.1160.0373.9290.821 SEM26.61538.1180.1361.0510.5892.4423.5540.1683.0243.314 SEM3.1542.6231.7952.4581.32121.1491.7181.2861.9431.2470.017 Mdx10Average0.7001.0250.6320.8873.1152.1630.43147.90114.950MdxAverage601.099375.2341.60121.96215.18219.19119.9170.95932.62739.738MdxAverage60.04631.09215.99323.74510.694451.36418.95524.34154.07916.4670.305 SEM0.0050.0080.0040.0050.015 0.0040.6020.188 SEM7.3053.9270.0100.3980.1430.4160.3100.0130.5650.673 SEM0.5580.4000.4560.5020.2565.0570.5100.3380.6480.3560.010 8 Week WT D24Average0.8081.4000.9501.3453.0601.6600.58567.89818.325WT D2Average624.250429.1781.47016.97812.34520.01520.8701.08536.17538.363WT D2Average78.17046.3038.85329.51016.390554.57520.490N/A SEM0.0570.0980.1070.0940.2120.1990.06210.5770.739 SEM40.50135.3940.0901.6331.0464.1513.6200.3768.5395.881 SEM4.8614.4552.6204.1292.38114.6664.039N/A Sgcg -/- D223Average0.8211.2830.8341.2662.9371.7000.57561.92115.196KO D2Average610.516423.7591.46320.73313.43917.48322.1390.80137.19134.881KO D2Average75.18044.1309.50225.37911.916470.64923.12925.08548.17914.4530.301 SEM0.0250.0380.0420.0520.0840.1020.0274.2780.771 SEM23.45516.3170.0540.7510.2941.0150.9370.0482.2532.218 SEM2.3792.3081.3911.2150.5948.6170.9170.8521.0710.4100.008 Mdx10Average0.8271.2260.7370.9803.5242.4550.44573.96822.790MdxAverage580.222381.3381.52526.67716.03219.38719.7221.04531.06053.191MdxAverage59.19630.89521.71631.47513.066414.90718.50527.13457.33019.0800.334 SEM0.0340.0680.0260.0320.0520.0680.0174.1880.634 SEM26.69116.3470.0421.2630.6921.5881.4480.1421.7661.947 SEM2.2941.5831.4731.5800.7247.8080.8880.6521.0430.6480.015 12 Week WT D26Average0.9651.4330.8721.1453.7072.5670.495101.40522.183WT D2Average628.920468.1371.36518.39214.12722.11825.6380.97529.40459.375WT D2Average58.17331.01825.40333.97216.060464.52025.00526.55752.07817.3100.334 SEM0.0220.0880.0530.0400.0650.2010.0096.8340.753 SEM18.22724.0920.0961.8900.9681.6893.4590.1962.6992.705 SEM6.0784.3014.6092.8372.11625.9791.6811.4253.0511.0390.015 Sgcg -/- D213Average0.8661.2940.8031.2513.0941.8220.55065.48819.120KO D2Average649.947466.5951.40419.48612.85518.75625.2800.77336.68839.648KO D2Average74.47143.53911.02928.61914.006489.47024.13927.63248.98415.7460.323 SEM0.0320.0550.0320.0530.0820.1120.0283.2180.734 SEM19.17315.9010.0340.9630.4091.0541.3230.0542.2082.552 SEM2.4922.3941.5841.2750.70311.6891.0000.8081.1640.3670.007 Mdx10Average0.8321.2030.7481.0113.7552.6780.42381.29826.780MdxAverage705.015437.7151.72226.89318.76620.95523.2670.94533.97862.497MdxAverage56.81929.45827.04535.45214.434403.46220.60126.94361.03119.0400.312 SEM0.0390.0620.0450.0600.0620.0770.0245.2941.306 SEM24.56641.3500.1402.0991.2400.9541.8930.0701.2082.301 SEM2.3391.5731.8391.7621.29122.1571.2810.6612.7441.0410.009 16 Week WT D210Average1.0571.6101.0761.5853.2381.8360.671103.32922.130WT D2Average641.327520.1001.25117.16113.99518.79522.7110.79435.95044.220WT D2Average74.83844.75512.64731.57315.553492.91423.21628.05348.33015.6350.326 SEM0.0570.0950.0410.0940.1180.2090.0405.0080.713 SEM30.82832.5850.0511.1040.7101.6131.8420.0532.9733.963 SEM4.8624.1623.4711.7231.11523.2191.6831.1582.0850.8110.016 Sgcg -/- D25Average0.9241.3760.8021.2423.1741.9320.54774.24419.760KO D2Average622.124457.7441.37116.70213.16221.51425.5940.84829.16041.164KO D2Average70.74039.78012.66228.50214.220500.61826.59625.63248.71816.9400.347 SEM0.0250.0430.0200.0600.1150.1900.0224.6730.568 SEM51.89337.8020.0851.5491.7671.9232.3860.0571.3993.631 SEM4.8533.9013.0121.3360.82227.8912.3800.8023.2901.4250.016 Mdx8Average0.8791.2980.7711.0703.7662.6310.43985.79127.438MdxAverage738.816468.0011.60725.82116.66422.36124.2400.97033.67663.749MdxAverage59.22931.63326.58937.16016.479443.52819.61129.19154.05917.4610.324 SEM0.0420.0680.0160.0590.0670.1570.0153.9081.228 SEM26.53927.7500.0892.3421.0591.5322.4990.0851.4972.806 SEM4.0473.2993.0411.4540.94718.7621.3240.8361.6880.5860.010 Roberts Supplemental Figure 2 Echocardiography