Clinical features of childhood-onset paroxysmal kinesigenic dyskinesia with PRRT2 gene mutations.
OBJECTIVE
To define better the phenotype and genotype of familial and sporadic cases of paroxysmal kinesigenic dyskinesia (PKD) caused by mutations in the PRRT2 gene presenting in the paediatric age group.


METHODS
We report the detailed clinical and molecular genetic features of 11 patients (six females, five males) with childhood-onset PRRT2-mutation-positive PKD.


RESULTS
Mean age at disease onset was 8 years 7.5 months (range 5-11y), and clinical presentation was characterized by daily short paroxysmal episodes of dystonia/dyskinesia. Most patients also had non-kinesigenic attacks in addition to the classical movement-induced paroxysmal episodes. One family demonstrated great phenotypic variability with PKD, infantile convulsions, and/or hemiplegic migraine affecting different family members with the same mutation. All patients in whom antiepileptics (carbamazepine/phenytoin) were tried showed a dramatic improvement with complete abolition of dyskinetic episodes.


CONCLUSIONS
Our case series provides a detailed clinical description of patients with PRRT2-PKD, and reports a spectrum of disease-causing mutations, thereby expanding both the clinical phenotype and mutation spectrum of disease.
Reta Lila Weston Institute of Neurological Studies, UCL Institute of Neurology, London, UK. laura.moriyama@ucl.ac.uk
Laura
L
Silveira-Moriyama
Alice R
AR
Gardiner
Esther
E
Meyer
Mary D
MD
King
Martin
M
Smith
Karl
K
Rakshi
Alasdair
A
Parker
Andrew A
AA
Mallick
Richard
R
Brown
Grace
G
Vassallo
Philip E
PE
Jardine
Marilisa M
MM
Guerreiro
Andrew J
AJ
Lees
Henry
H
Houlden
Manju A
MA
Kurian
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D002648:Child; D002675:Child, Preschool; D018389:Codon, Nonsense; D015331:Cohort Studies; D020820:Dyskinesias / Q000235:genetics*; D020936:Epilepsy, Benign Neonatal / Q000235:genetics*; D005260:Female; D016368:Frameshift Mutation; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D008875:Middle Aged; D020325:Migraine with Aura / Q000235:genetics; D009069:Movement Disorders / Q000235:genetics*; D009154:Mutation; D020125:Mutation, Missense; D009419:Nerve Tissue Proteins / Q000235:genetics*; D010641:Phenotype; D012640:Seizures / Q000235:genetics*; D006113:United Kingdom; D055815:Young Adult
D018389:Codon, Nonsense; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C569370:PRRT2 protein, human