Mutations in the PRRT2 gene can cause paroxysmal kinesigenic dyskinesia with infantile convulsions (PKD/IC, also called infantile convulsions and choreoathetosis or ICCA), isolated PKD, or benign familial infantile seizures (BFIS). PKD is characterized by involuntary movements triggered by the initiation of sudden motion or a change in the velocity of movements, such as going from walking to running. The attacks typically last only several seconds and result in dystonia, chorea, athetosis, or ballism. The involuntary movements do not cause loss of consciousness. Attacks typically begin in childhood, and the frequency gradually decreases with age. Treatment with anticonvulsants is usually effective in controlling the attacks. BFIS results in generalized tonic-clonic and complex partial seizures that typically occur in clusters between 3-24 months of age. The seizures typically resolve by age 2, and most individuals with BFIS have a good outcome and normal cognitive development. Mutations in the PRRT2 gene cause variable clinical features, even among individuals in the same family. Some individuals may experience both PKD and seizures while others exhibit PKD or seizures only.