Ataxia, Attention deficit hyperactivity disorder, Autism, Behavioral abnormality, Bradykinesia, Brain atrophy, Cerebral atrophy, Decreased fetal movement, Delayed speech and language development, Developmental regression, Difficulty walking, Downslanted palpebral fissures, Dysarthria, Dyskinesia, Dysphagia, Dystonia, EEG with multifocal slow activity, Elevated circulating creatine kinase concentration, Encephalopathy, Epileptic encephalopathy, Eyelid apraxia, Failure to thrive, Fatigue, Feeding difficulties, Gait ataxia, Gastroesophageal reflux, Generalized hypotonia, Global developmental delay, High forehead, Hypodontia, Hypomimic face, Hypoplasia of the corpus callosum, Hyporeflexia, Hypsarrhythmia, Impulsivity, Inability to walk, Increased circulating lactate concentration, Intellectual disability, Intellectual disability, profound, Involuntary movements, Leg muscle stiffness, Limb hypertonia, Mental deterioration, Microcephaly, Myoclonus, Nystagmus, Optic atrophy, Parkinsonism, Pes cavus, Poor head control, Postural instability, Progressive neurologic deterioration, Ptosis, Reduced tendon reflexes, Resting tremor, Retinal degeneration, Rigidity, Scoliosis, Seizure, Short stature, Short stepped shuffling gait, Shuffling gait, Slowed slurred speech, Spastic tetraplegia, Spasticity, Staring gaze, Status epilepticus, Supranuclear gaze palsy, Tremor, Unsteady gait, Visual impairment, Weak voice