Figure 1.

Electron microscopy of muscle fibers in longitudinal section of a patient with Pompe disease. (A) Pre-treatment muscle fiber. Two glycogen-filled lysosomes under sarcolemma are enlarged in the inset. Massive glycogen accumulations are also present within intermyofibrillar spaces. (B) Post treatment muscle fiber shows relevant glycogen reduction. A low amount of glycogen granules (arrows) still appears located within some intermyofibrillar spaces. Scale bar = 1 µm. Inset scale bar = 0.5 µm.