PLEC and Menkes disease: In skeletal muscle samples from EBS-MD patients (12,13), as well as from muscle-restricted conditional plectin knockout mice (MCK-Cre/cKO) (14), remarkable mitochondrial alterations have been observed, including altered cristae structure and massive subsarcolemmal aggregation of mitochondria, and the presence of fibers with attenuated levels of mitochondria (15).