Objective The aim of this study is to clarify the clinical characteristics and genetic features of benign infantile epilepsy with Proline-rich transmembrane protein 2（PRRT2）mutation.

Method The clinical data and genetic results of 40 patients with PRRT2 mutation benign infantile epilepsy were analyzed.

Result Fourty benign infantile epilepsy patients were recruited in this study, The age at onset ranged from 3 to 15 months. All patients presented focal seizures with or without secondary generalization. A cluster of seizures was observed in 20 patients. 36 patients were treated with antiepileptic drugs and 4 patients without medication. 24 patients became seizure free before 12 months, 10 patients during 12～24 months and 2 patients during 24～36 months. 2 patients developed paroxysmal kinesigenic dyskinesia in 30 months and 12 years respectively. 34 affected pedigree members had a history of paroxysmal episodes in 24 families, including 19 infantile afebrile convulsion, 6 paroxysmal kinesigenic dyskinesia, 8 infantile convulsion and paroxysmal kinesigenic dyskinesia during adulthood, 1 infantile febrile convulsion. All cases had PRRT2 mutations, 7 of complete PRRT2 deletion, 33 of PRRT2 heterozygous mutation.

Conclusion Benign infantile epilepsy with PRRT2 mutation is characterized by early seizure onset, focal seizures with or without secondary generalization, a high incidence of a cluster of seizures, short duration of seizure cessation. Partial patients may develop paroxysmal kinesigenic dyskinesia. Most of PRRT2 mutations are heterozygous mutation, a few is a complete deletion.