PLEC and Menkes disease: Myopathological analyses of skeletal muscle specimens from all three EBS-MD patients with genetically confirmed PLEC mutations revealed a marked myodegenerative pattern with increased endomysial connective and fatty tissue, highly variable fiber size diameters (5 to 145 μm), predominance of type 1 fibers, fiber splitting as well as de- and regenerating fibers (Fig. 2a).