Novel mutation of the gene in two cases of paroxysmal kinesigenic dyskinesia: Two case reports.

Paroxysmal kinesigenic dyskinesia (PKD) is a rare condition characterized by recurrent brief episodes of dystonia, chorea, athetosis or any combination of these, without alterations of consciousness. The () gene has been widely investigated as a causative gene of PKD. To date, a cluster of pathogenic variants associated with PKD have been identified in the gene. In the present case report, two Chinese patients with sporadic PKD are discussed. Genetic analysis revealed a heterozygous missense mutation, c.955G>T (p.Val319Leu) in exon 3 of the gene. Compared with the commonly reported clinical manifestation of PRRT2-associated PKD, the patients in this report showed several primary distinctive features. The mutations identified in the present analysis expand upon the mutation spectrum of the gene, and this newly found variant further reinforces the importance of the gene in PKD.