Electroencephalogram features of paroxysmal kinesigenic dyskinesia and influence of PRRT2 mutations in these features

Abstract

Objective To explore the electroencephalography(EEG)features of paroxysmal kinesigenic dyskinesia(PKD)and analyze the influence of proline-rich transmembrane protein 2(PRRT2)mutations in EEG features. Methods Sixty patients with PKD were collected in our hospital from January 2006 to December 2014. The patients were classified into different subtypes according to the paroxysmal symptoms: 27 with pure PKD, 2 with PKD plus benign familial infantile convulsion(ICCA), 4 with PKD plus febrile seizure(FS), and 27 with PKD plus unclassified epilepsy. Video EEG monitoring was performed in all patients. The features of EEG in different subtypes of PKD were analyzed. PRRT2 gene mutations were screened in 39 patients. The EEG features were compared between the patients with and without PRRT2 gene mutations. Results Interictal EEG abnormalities were presented in 31 patients(51.7%), including 12(44.4%)with pure PKD, one(50%)with ICCA, 18(66.7%)with PKD plus unclassified epilepsy. Interictal EEG abnormalities were presented as diffused slowing wave(n=9, 29%), focal slowing wave(n=11, 35.5%), and focal epileptiform discharges(n=11, 35.5%). There were no significant differences in the percentage of diffuse slowing discharges(14.8% vs. 18.5% , P=0.500), focal slowing discharges(14.8% vs. 25.9% , P=0.311), and focal epileptiform discharges(14.8% vs. 25.9%, P=0.311)between patients with pure PKD and PKD plus unclassified epilepsy. PRRT2 gene mutations were identified in 21 patients(53.8%). The ratio of EEG abnormalities between groups with and without PRRT2 gene mutations was not significantly different(57.1% vs. 44.4%, P>0.05). Conclusions Interictal EEG abnormalities can be presented in patients with pure PKD or PKD plus epilepsy. PRRT2 gene mutations could not influence EEG features in PKD. Key words: Paroxysmal kinesigenic dyskinesia; Electroencephalography; Proline-rich transmembrane protein 2; Epilepsy