Paroxysmal dyskinesias are movement disorders characterized by sudden episodes of involuntary movements. They are divided into kinesigenic, non-kinesigenic, and exercise-induced dyskinesias. Emphasis is made on the importance of the clinical history and fully describing the episodes in the differential diagnosis. The case is presented of a twelve year-old female with paroxysmal episodes of tongue torsion and dystonic postures of the upper limbs when start running or descending stairs and in the beginning of physical exercise, which ceased spontaneously seconds later. Some episodes were triggered by stress. In family history her father, paternal uncle, and sister also had paroxysmal movements. Interictal neurological examination was normal. Laboratory tests revealed a mutation in PRRT2 gene, which is related to neurological disorders such as paroxysmal kinesigenic dyskinesia, infantile convulsions and choreoathetosis migraine, episodic ataxia, paroxysmal torticollis, and intellectual disability. Treatment with carbamazepine was effective.