Fig. 1

Histological, immunohistochemical, and ultrastructural studies in patient’s muscle. A Light microscopy observations of MTG showed moderately increased variation in fiber size with a consistent number of hypotrophic fibers and the presence of abnormal subsarcolemmal granules in several fibers. B Staining for COX activity shows the presence of large mitochondria at the periphery of fibers and central areas lacking any activity (* indicates lack of COX activity due to mitochondrial depletion in those areas/fibers). Immunofluorescence staining for p62 (C) and LC3A (D) was positive in some fibers. Caveolin-3 was used for membrane staining and nuclei were counterstained with DAPI. E–H Representative images of the main alterations in skeletal muscle and in mitochondria morphology. E Minor abnormalities of the of Z-line (indicated by an arrow), mitochondrial alterations including giant mitochondria (F), mitochondria with globular inclusions (G), and swollen mitochondria (H). Scale bars: A, 400 µm; B–D, 250 µm, E–F 2.27 µm; G, 0.83 µm; H, 1.43 µm