Fig. 3

Muscle biopsy spectrum. a and b: Case 7: NADH and COX stainings, respectively showing presence of mutiple cores (magnification 20x). c: Case 8: COX staining of muscle sections showing severe alteration of intermyofibrillar network such as moth eaten fibres (magnification 40x). d: Case 21: NADH staining displaying hyaline bodies (magnification 40x). e: Case 10. This case has already been described in reference Ruggiero et al. NADH staining presenting fibre type disproportion with small type 1 fibres representing the majority of fibres and larger type 2 fibres (magnification 10x). f: Case 8. ATP 9.6 (magnification 10x) reveals pronounced type 1 predominancy or nearly uniformity. Most fibres are type 1 with only few scattered type 2 fibres. g-l: Case 4 had two muscle biopsies taken at different ages. In the first biopsy at age 7 years, COX (g) and NADH (h) staining showed clear cores in numerous fibres. The same staining (i and l) did not show cores, however the inter-myofibrillar network appeared diffusely pale and thin in the second biopsy performed ten years later