Benign infantile convulsion as a diagnostic clue of paroxysmal kinesigenic dyskinesia: a case series

Matsumoto, Naoya; Takahashi, Satoru; Okayama, Akie; Araki, Akiko; Azuma, Hiroshi

doi:10.1186/1752-1947-8-174

Cited by 5 publications

(5 citation statements)

References 16 publications

(17 reference statements)

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“…Of note, these three variants were not co‐segregated with the disease in the family pedigrees reported previously . In addition, eight variants (p.R266W, p.S275F, p.A291V, p.G305R, p.A306T, p.S317N, p.G324E, and p.I327M) were reported to co‐segregate with PKD or BFIS in multiple affected family members . They were predicted to be deleterious by SIFT, Polyphen‐2, and MutationTaster.…”

Section: Resultsmentioning

confidence: 76%

Functional study and pathogenicity classification of PRRT2 missense variants in PRRT2‐related disorders

Zhao

Chen

et al. 2019

CNS Neurosci Ther

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Aims PRRT2 variants are associated with various paroxysmal disorders. To date, more than 90 PRRT2 variants have been reported in PRRT2‐related disorders. Lack of functional study in majority of missense variants makes their pathogenicity uncertain. We aim to evaluate the clinical significance of PRRT2 missense variants by performing in vitro experiments.MethodsWe systematically reviewed PRRT2‐related disorders and summarized reported PRRT2 missense variants. Protein expression and subcellular localization of mutant PRRT2 were investigated in mammal cells. American College of Medical Genetics and Genomics (ACMG) guidelines were used to analyze the pathogenicity of PRRT2 missense variants.ResultsA total of 29 PRRT2 missense variants were identified in PRRT2‐related disorders. Ten variants were observed to affect both subcellular localization and protein level, three variants only affect membrane localization, and two variants only affect protein level. According to ACMG guidelines, 15 variants were finally classified as “likely pathogenic”, three as “benign”, three as “likely benign”, and eight as “uncertain significance” variants. The likely pathogenic variants were concentrated in the C‐terminal of PRRT2.ConclusionsThe pathogenicity of eight uncertain significance variants needs further investigation. C‐terminal of PRRT2 is crucial for its physiological function.

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Section: Resultsmentioning

confidence: 76%

Functional study and pathogenicity classification of PRRT2 missense variants in PRRT2‐related disorders

Zhao

Chen

et al. 2019

CNS Neurosci Ther

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“…There have been several reports on PRRT2 mutations in BIE and/or PKD in Japanese children [8][9][10][19][20][21]. However, most reports included few patients.…”

Section: Introductionmentioning

confidence: 99%

PRRT2 mutations in Japanese patients with benign infantile epilepsy and paroxysmal kinesigenic dyskinesia

Okumura

Shimojima

Kurahashi

et al. 2019

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This study was performed to clarify the clinical features of Japanese patients with PRRT2 mutations. Methods: The PRRT2 gene was analyzed in 135 patients with benign infantile epilepsy (BIE) or paroxysmal kinesigenic dyskinesia (PKD) using a direct sequencing method: 92 patients had BIE alone, 25 had both BIE and PKD, and 18 had PKD alone. Of the cases, 105 were familial, and 30 were sporadic. Clinical information was collected using a structured questionnaire. Results: PRRT2 mutations were identified in 104 patients. Among the familial cases, PRRT2 mutations were found in at least one individual in 21 of 28 families with BIE alone, in 26 of 27 families with infantile convulsions and choreoathetosis, and in 2 of 3 families with PKD alone. Among the sporadic cases, PRRT2 mutations were observed in 7 of 25 patients with BIE alone, in 1 of 1 patient with BIE and PKD, and in 3 of 4 patients with PKD alone. The c.649dupC mutation was the most frequent, followed by the c.981C > G mutation. Among the patients with epilepsy, the median age at BIE onset was 5 months, the median age at the last seizure was 6 months, and the median number of seizures was 5. Conclusion: PRRT2 mutations were found in 68% of Japanese probands with BIE or PKD. The phenotypes of BIE associated with PRRT2 mutations were consistent with those of BIE diagnosed clinically.

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“…4,5 Patients with PKD can be misdiagnosed with epilepsy or psychogenic illness 6 ; an aetiological diagnosis will require genetic analysis of PRRT2 gene, the most common disease-causing gene for PKD.…”

Section: Discussionmentioning

confidence: 99%

A common PRRT2 mutation in familial paroxysmal kinesigenic dyskinesia in Hong Kong: a case series of 16 patients

et al. 2016

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Patient 1 was a 47-year-old woman who presented with paroxysmal abnormal movement since childhood. She was first seen in 2004. The attack was characterised by dystonic painful posture with upward or downward deviation of the eyes, head turning, shoulder abduction and extensions, lower limb dystonia, impaired speech, and occasionally stepping movements, with preserved consciousness. The attacks lasted for 1 to 2 minutes with a frequency of up to 8 times a day. Each attack was precipitated by stress or being startled, for example, being approached by a car unexpectedly when crossing the road, frightened by a cockroach, a sudden phone call, or an abrupt movement. Occasionally, the attack could occur during sleep. There was no incontinence. The patient had normal intelligence. Physical examination, biochemical tests, computed tomography of the brain, and electroencephalography were normal. The attacks were controlled with carbamazepine and frequency of attacks reduced to fewer than 3 times a day and each episode was shortened to 10 to 20 seconds. The patient also had a history of seizure of unknown aetiology in childhood. She had a strong family history; her daughter has presented with seizure on two to three occasions since the age of 10 months and had been taking an anticonvulsant for 2 years. Since then she had experienced no further seizures and by the age of 4 years no antiepileptic drug or follow-up has been required. Two older sisters and a nephew of the proband also had childhood seizures. Family 2Patient 2 was a 26-year-old woman who presented with paroxysmal kinesigenic dyskinesia (PKD) since the age of 8 years. The patient first presented with episodes of afebrile seizure at 7 months old in 1997. She was prescribed phenobarbitone and required no further medication or follow-up after the age of 3 years. The current involuntary movement affected all limbs with the right side being most affected. Each attack lasted for a few seconds to less than 3 minutes without loss of consciousness. Each episode was triggered by sudden body movement, anxiety, or deprived sleep. Frequency of attacks could reach up to 6 times a day. The patient claimed she could occasionally partially control the symptoms. Physical examination, biochemical tests, and brain imaging were unremarkable. Her brother was also affected by PKD. The attack was controlled by carbamazepine; a missed dose would usually lead to relapse. Family 3Patient 3 was a 14-year-old boy who presented in 2004 with chorea-like movement of the four limbs since the age of 18 months. Each attack lasted for about 15 to 20 seconds and there was no impaired consciousness. The frequency of attacks could reach up to 10 times a day. The attacks were triggered after running or waking up from sleep. A good clinical response was achieved with carbamazepine. The attacks recurred only after a missed dose. Physical examination, biochemical investigations, and brain imaging were unremarkable and he had normal development and intelligence. Five paternal family CASE REPORT

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Benign infantile convulsion as a diagnostic clue of paroxysmal kinesigenic dyskinesia: a case series

Cited by 5 publications

References 16 publications

Functional study and pathogenicity classification of PRRT2 missense variants in PRRT2‐related disorders

Functional study and pathogenicity classification of PRRT2 missense variants in PRRT2‐related disorders

PRRT2 mutations in Japanese patients with benign infantile epilepsy and paroxysmal kinesigenic dyskinesia

A common PRRT2 mutation in familial paroxysmal kinesigenic dyskinesia in Hong Kong: a case series of 16 patients

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