*Dystonia: involuntary muscle contractions 
*Axial hypotonia: low muscle tone and strength
*Dysarthria: impairment in muscles used for speech
*Muscle stiffness and tremors
*Seizures 
*Coordination and balance impairment
*Oculogyric crises: abnormal rotation of the eyes
The oculogyric crises usually occur in the later half of the day and during these episodes patients undergo extreme agitation and irritability along with uncontrolled head and neck movements. Apart from the aforementioned symptoms, patients can also display parkinsonism, sleep disturbances, small head size (microcephaly), behavioral abnormalities, weakness, drooling, and gastrointestinal symptoms.