PRRT2 Mutations Cause Benign Familial Infantile Epilepsy and Infantile Convulsions with Choreoathetosis Syndrome

Sarah E. Heron, Bronwyn E. Grinton, Sara Kivity, Zaid Afawi, Sameer M. Zuberi, James N. Hughes, Clair Pridmore, Bree L. Hodgson, Xenia Iona, Lynette G. Sadleir, James Pelekanos, Eric Herlenius, Hadassa Goldberg-Stern, Haim Bassan, Eric Haan, Amos D. Korczyn, Alison E. Gardner, Mark A. Corbett, Jozef Gécz, Paul Q. Thomas, John C. Mulley, Samuel F. Berkovic, Ingrid E. Scheffer, Leanne M. Dibbens

Benign familial infantile epilepsy (BFIE) is a self-limited seizure disorder that occurs in infancy and has autosomal-dominant inheritance. We have identified heterozygous mutations in PRRT2, which encodes proline-rich transmembrane protein 2, in 14 of 17 families (82%) affected by BFIE, indicating that PRRT2 mutations are the most frequent cause of this disorder. We also report PRRT2 mutations in five of six (83%) families affected by infantile convulsions and choreoathetosis (ICCA) syndrome, a familial syndrome in which infantile seizures and an adolescent-onset movement disorder, paroxysmal kinesigenic choreoathetosis (PKC), co-occur. These findings show that mutations in PRRT2 cause both epilepsy and a movement disorder. Furthermore, PRRT2 mutations elicit pleiotropy in terms of both age of expression (infancy versus later childhood) and anatomical substrate (cortex versus basal ganglia).