Symptoms

Cerebral stroke-like lesions in a nonvascular pattern (brain lesions that do not appear like a regular stroke on imaging) Basal ganglia disease (physical dysfunction, such as would occur with Parkinson’s disease) Encephalopathy (brain disease) recurrent or with low/ moderate dosing of valproate (a medicine used to treat epilepsy, bipolar disease, and migraines) Neurodegeneration (the progressive loss of structure or function of neurons, including death of neurons) Epilepsia partialis continua (recurrent epileptic seizures that affect specific areas and recur every few seconds or minutes for extended periods) Myoclonus (jerky contraction of groups of muscles) Ataxia (loss of control of body movements) MRI findings consistent with Leigh disease (in basal ganglia or brain stem) Characteristic magnetic resonance spectrometry (MRS) peaks