PAS staining, p62 immunohystochemistry and Toluidine blue staining of arrector pili muscles from control and Pompe patients skin biopsies. A-B: The different types of glycogen accumulation (granular glycogen versus membrane bound form) are indistinguishable with PAS staining of controls (A) and patients (B). C-D: Toluidine blue staining of semithin sections shows granular glycogen accumulations in control (arrows, C) and glycogenosomes (arrows, D) in Pompe patient biopsies. E-F: Immunohistochemistry against p62 (a marker for autophagy) shows accumulations in patient arrector pili muscle (F, arrows) but not in healthy controls (E). Scale bar for all parts: 20 μm.