Motoyama R, Matsudaira T, Terada K, Usui N, Yoshiura KI, Takahashi Y. PRRT2 mutation in a Japanese woman: Adult-onset focal epilepsy coexisting with movement disorders and cerebellar atrophy.
Epilepsy Behav Rep 2022;
19:100554. [PMID:
35712060 PMCID:
PMC9194843 DOI:
10.1016/j.ebr.2022.100554]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 04/23/2022] [Accepted: 05/16/2022] [Indexed: 11/17/2022] Open
Abstract
Mutation of the PRRT2 gene in a Japanese woman resulted in the c.604_607del variant.
Her clinical features presented with focal epilepsy, cerebellar atrophy, paroxysmal kinesigenic dyskinesia, and paroxysmal non-kinesigenic dystonia (PNKD).
Video-EEG monitoring revealed that her epilepsy arose from the left temporal region.
Low dose lamotrigine was effective for her epilepsy and PNKD.
Proline-rich transmembrane protein 2 (PRRT2) was confirmed as the causative gene of paroxysmal kinesigenic dyskinesia (PKD) as shown by genome-wide linkage analyses. PRRT2 mutations are also associated with benign familial infantile seizures, infantile convulsions and choreoathetosis, and childhood absence epilepsy, but few reports have investigated adult-onset epilepsy. We describe here a rare presentation of adult-onset focal epilepsy with a PRRT2 mutation in a 31-year-old woman who showed cerebellar atrophy, familial paroxysmal kinesigenic dyskinesia, and paroxysmal non-kinesigenic dystonia. Video-electroencephalography (EEG) demonstrated focal impaired awareness seizures, in which ictal EEG changes showed left temporal onset with rhythmic theta activity over the left temporal region. Magnetic resonance imaging showed mild cerebellar atrophy. The administration of lamotrigine 50 mg/day resulted in freedom from her seizures and lamotrigine 150 mg/day reduced paroxysmal non-kinesigenic dystonia. Furthermore, she had a rare frameshift mutation, c.604_607del, p.Ser202fs of which the pathogenicity has been reported in ClinVar, but it has not been reported in Japan. Mutation of the PRRT2 gene can cause adult-onset epilepsy, paroxysmal non-kinesigenic movement disorder, and cerebellar atrophy, suggesting an expanding clinical phenotypic spectrum associated with PRRT2 mutations.
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