Cardiomyopathy, Cerebellar atrophy, Cerebral atrophy, Chronic fatigue, Cognitive impairment, Cogwheel rigidity, Cytochrome C oxidase-negative muscle fibers, Decreased activity of mitochondrial respiratory chain, Delayed gross motor development, Depletion of mitochondrial DNA in muscle tissue, Depression, Developmental regression, Difficulty standing, Difficulty walking, Distal muscle weakness, Distal sensory impairment, Dysarthria, Dyschromatopsia, Dysphagia, EMG: myopathic abnormalities, Elevated circulating creatine kinase concentration, Exercise intolerance, External ophthalmoplegia, Facial diplegia, Facial palsy, Failure to thrive in infancy, Feeding difficulties in infancy, Generalized amyotrophy, Generalized hypotonia, Generalized muscle weakness, Generalized-onset seizure, Gowers sign, Hand muscle weakness, Hearing impairment, Hyporeflexia, Hypotonia, Inability to walk, Infantile encephalopathy, Infantile sensorineural hearing impairment, Intellectual disability, progressive, Irritability, Lactic acidosis, Limb muscle weakness, Loss of ability to walk in early childhood, Mask-like facies, Mitochondrial myopathy, Motor delay, Motor deterioration, Muscle fiber atrophy, Muscle stiffness, Muscle weakness, Myalgia, Myopathy, Ophthalmoparesis, Optic atrophy, Optic neuritis, Paresthesia, Parkinsonism with favorable response to dopaminergic medication, Peripheral neuropathy, Progressive external ophthalmoplegia, Progressive proximal muscle weakness, Proximal muscle weakness, Ptosis, Ragged-red muscle fibers, Recurrent pneumonia, Respiratory distress, Respiratory insufficiency, Respiratory insufficiency due to muscle weakness, Scapular winging, Scoliosis, Seizure, Sensory axonal neuropathy, Severe sensorineural hearing impairment, Shuffling gait, Skeletal muscle atrophy, Spinal muscular atrophy, Stooped posture, Ventilator dependence with inability to wean, Visual impairment, Weak voice, Weakness of facial musculature

muscle phenotype, postnatal lethality, complete penetrance, weakness