PRRT2 Mutation and Serum Cytokines in Paroxysmal Kinesigenic Dyskinesia

Objective: Paroxysmal kinesigenic dyskinesia (PKD) is a rare movement disorder PRRT2 gene mutations have been reported to cause PKD. However, the pathophysiological mechanism of PKD remains unclear, and it is unknown whether an inflammatory response is involved in the occurrence of this disease. We aimed to investigate the symptomatology, genotype, and serum cytokines of patients with PKD.

Methods: We recruited 21 patients with PKD, including 7 with familial PKD and 14 with sporadic PKD. Their clinical features were investigated, and blood samples were collected, and PRRT2 mutations and cytokine levels were detected.

Results: The mean age at PKD onset was 12.3±2.2 years old. Dystonia was the most common manifestation of dyskinesia, and the limbs were the most commonly affected parts. All attacks were induced by identifiable kinesigenic triggers, and the attack durations were brief (<1 min). Four different mutations from 9 probands were identified in 7 familial cases (71.4%) and 14 sporadic cases (28.6%). Two of these mutations (c.649dupC, c.620_621delAA) had already been reported, while other 2 (c.1018_1019delAA, c.1012+1G>A) were previously undocumented. The tumor necrosis factor (TNF)-α level in the PKD group was significantly higher than that in the age- and sex-matched control group (P=0.025). There were no significant differences in the interleukin (IL)-1β, IL-2R, IL-6, IL-8, or IL-10 levels between the two groups.

Conclusion: In this study, we summarized the clinical and genetic characteristics of PKD. We found that the serum TNF-α levels were elevated in patients clinically diagnosed with PKD, suggesting that an inflammatory response is involved in the pathogenesis of PKD.