Paroxysmal Kinesigenic Dyskinesia Secondary to Novel Variant in PRRT2: A Case Report

Abstract

Paroxysmal kinesigenic dyskinesia (PKD) is a movement disorder characterized by frequent, brief episodes of choreiform or dystonic movements, often triggered by voluntary movement or a startle sensation. Here, we report a case of PKD associated with a novel variant in PRRT2 gene. A 19-year-old male with no medical history presented with hyperkinetic movement disorder symptoms consistent with PKD. Clinical evaluation, laboratory studies, and genetic testing were performed to confirm the diagnosis. Treatment with carbamazepine was initiated, and the patient's response was monitored over a 9-month period. The patient exhibited classic clinical criteria for PKD, including brief episode duration, an identified kinesigenic trigger, and responsiveness to pharmacological treatment. Genetic testing revealed a pathogenic variant in PRRT2 gene not previously reported in association with PKD. Treatment with carbamazepine led to complete resolution of symptoms, with sustained improvement observed during follow-up. This case highlights the importance of considering PKD in the differential diagnosis of hyperkinetic movement disorders and emphasizes the role of genetic testing in confirming the diagnosis. Furthermore, it underscores the efficacy of carbamazepine in managing PKD symptoms associated with PRRT2 gene. Further research is warranted to elucidate the underlying pathophysiological mechanisms and optimize treatment strategies for PKD.

Keywords

dyskinesias - prrt2 protein - genetics - case reports

Publication History

Received: 14 March 2024

Accepted: 27 April 2024

Article published online:
03 June 2024

• References

• 1 Ebrahimi-Fakhari D, Kang KS, Kotzaeridou U, Kohlhase J, Klein C, Assmann BE. Child Neurology: PRRT2-associated movement disorders and differential diagnoses. Neurology 2014; 83 (18) 1680-1683
• 2 Bruno MK, Hallett M, Gwinn-Hardy K. et al. Clinical evaluation of idiopathic paroxysmal kinesigenic dyskinesia: new diagnostic criteria. Neurology 2004; 63 (12) 2280-2287
• 3 Chen W-J, Lin Y, Xiong Z-Q. et al. Exome sequencing identifies truncating mutations in PRRT2 that cause paroxysmal kinesigenic dyskinesia. Nat Genet 2011; 43 (12) 1252-1255
• 4 Méneret A, Gaudebout C, Riant F, Vidailhet M, Depienne C, Roze E. PRRT2 mutations and paroxysmal disorders. Eur J Neurol 2013; 20 (06) 872-878
• 5 Xu J-J, Li H-F, Wu Z-Y. Paroxysmal kinesigenic dyskinesia: genetics and pathophysiological mechanisms. Neurosci Bull 2023
• 6 Becker F, Schubert J, Striano P. et al. PRRT2-related disorders: further PKD and ICCA cases and review of the literature. J Neurol 2013; 260 (05) 1234-1244
• 7 Zeng Q, Yang X, Zhang J. et al. Genetic analysis of benign familial epilepsies in the first year of life in a Chinese cohort. J Hum Genet 2018; 63 (01) 9-18
• 8 Balagura G, Riva A, Marchese F. et al. Clinical spectrum and genotype-phenotype correlations in PRRT2 Italian patients. Eur J Paediatr Neurol 2020; 28: 193-197
• 9 Landolfi A, Barone P, Erro R. The spectrum of PRRT2-associated disorders: update on clinical features and pathophysiology. Front Neurol 2021; 12: 629747
• 10 van Vliet R, Breedveld G, de Rijk-van Andel J. et al. PRRT2 phenotypes and penetrance of paroxysmal kinesigenic dyskinesia and infantile convulsions. Neurology 2012; 79 (08) 777-784