Girl with a PRRT2 mutation and infantile focal epilepsy with bilateral spikes.

This paper documents the case of a female Japanese patient with infantile focal epilepsy, which was different from benign infantile seizures, and a family history of infantile convulsion and paroxysmal choreoathetosis. The patient developed partial seizures (e.g., psychomotor arrest) at age 14 months. At the time of onset, interictal electroencephalography (EEG) showed bilateral parietotemporal spikes, but the results of neurologic examination and brain magnetic resonance imaging were normal. Her seizures were well controlled with carbamazepine, and she had a normal developmental outcome. EEG abnormalities, however, persisted for more than 6 years, and the spikes moved transiently to the occipital area and began to resemble the rolandic spikes recognized in benign childhood epilepsy. Her father had paroxysmal kinesigenic dyskinesia, with an onset age of 6 years, and her youngest sister had typical benign infantile seizures. Genetic analysis demonstrated that all affected members had a heterozygous mutation of c.649_650insC in the proline-rich transmembrane protein-2 (PRRT2) gene. This case indicates that the phenotypic spectrum of infantile seizures or epilepsy with PRRT2-related pathology may be larger than previously expected, and that genetic investigation of the effect of PRRT2 mutations on idiopathic seizures or epilepsy in childhood may help elucidate the pathological backgrounds of benign childhood epilepsy.