DMD and neuromuscular disease caused by qualitative or quantitative defects of dystrophin: Immunoblotting indicated that the expression of this short spleen-associated isoform of dystrophin is not affected in dystrophinopathy (Figures 1C and 1D), but the full-length Dp427-M isoform of dystrophin was clearly shown to be absent from mdx-4cv gastrocnemius muscle, as illustrated in Figures 2C–2E.