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Abstract
Objective: We aimed to investigate the clinical and genetic features of paroxysmal kinesigenic dyskinesia (PKD) in a large population and to analyze the genotype–phenotype correlation of PKD.
Methods: We analyzed clinical manifestations and conducted PRRT2 screening in 110 patients with PKD. Clinical data were compared between 91 probands with and without PRRT2 mutations.
Results: Among the enrolled participants (45 from 26 families, 65 sporadic cases), 8 PRRT2 mutations were detected in 20 PKD families (76.9%) and 14 sporadic cases (21.5%), accounting for 37.4% (34/91) of the study population. Five mutations (c.649dupC, c.649delC, c.487C>T, c.573dupT, c.796C>T) were already reported, while 3 mutations (c.787C>T, c.797G>A, c.931C>T) were undocumented. A patient harboring a homozygous c.931C>T mutation was shown to have inherited the mutation via uniparental disomy. Compared with non-PRRT2 mutation carriers, the PRRT2 mutation carriers were younger at onset, experienced longer attacks, and tended to present with complicated PKD, combined phenotypes of dystonia and chorea, and a positive family history. A good response was shown in 98.4% of the patients prescribed with carbamazepine.
Conclusions: PRRT2 mutations are common in patients with PKD and are significantly associated with an earlier age at onset, longer duration of attacks, a complicated form of PKD, combined phenotypes of dystonia and chorea, and a tendency for a family history of PKD. A patient with uniparental disomy resulting in a homozygous c.931C>T mutation is identified in the present study. Carbamazepine is the first-choice drug for patients with PKD, but an individualized treatment regimen should be developed.
GLOSSARY
- BFIS=
- benign familial infantile seizures;
- EKD=
- episodic kinesigenic dyskinesia;
- PKD=
- paroxysmal kinesigenic dyskinesia;
- PxD=
- paroxysmal dyskinesia;
- SNP=
- single-nucleotide polymorphism;
- UPD=
- uniparental disomy
Footnotes
↵* These authors contributed equally to this work.
Go to Neurology.org for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the article.
Supplemental data at Neurology.org
- Received January 6, 2015.
- Accepted in final form July 1, 2015.
- © 2015 American Academy of Neurology
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