Mitochondrial genome large rearrangements in the skeletal muscle of a patient with PMA

Sir, Progressive muscular atrophy is a motor neuron disease (MND) characterized by selective lower motor neuron involvement [1]. MND pathogenesis is unknown and different mechanisms, including oxidative stress, may be involved [2]. Mitochondrial (mt) abnormalities have been observed in motor neurons of patients with MND [2], and MND patients carrying pathogenic mtDNA alteration have been reported [3]. A 63-year-old woman presented with a 4-year history of proximal upper limb muscle weakness and hypotrophy. Informed consent was obtained. Neurological examination revealed muscle weakness, hypotrophy and fasciculations with the absence of deep tendon reflexes in upper limbs. Cranial nerves and lower limbs function were normal. Laboratory examinations, SOD1, and SMA analysis were normal. Electromyography of the four limb muscles showed diffuse chronic denervation with fibrillations. Motor, sensory evoked potentials were normal. Magnetic Resonance Imaging (MRI) of brain was normal, whilst MRI of the spinal cord revealed cervical and lumbar disks protrusion. The muscular weakness slowly