Sage Journals: Discover world-class research

Abstract

The differential diagnosis of fever-induced movement disorders in childhood is broad. Whole exome sequencing has yielded new insights into those cases with a suspected genetic basis. We report the case of an 8-year-old boy with a history of neonatal seizures who presented with near-continuous hyperkinetic movements of his limbs during a febrile illness. Initial diagnostic testing did not explain his abnormalities; however, given the suspicion for a channelopathy, whole exome sequencing was performed and it demonstrated a de novo pathogenic heterozygous variant in KCNQ2. There is an expanding phenotypic spectrum of heterozygous alterations in KCNQ2; however, this report provides the first description of a pathogenic KCNQ2 variant fever-induced hyperkinetic movement disorder in childhood. We also review the literature of cases previously published with the same pathogenic variant.

Keywords

chorea next generation sequencing pediatrics genetics mutation

Get full access to this article

View all access options for this article.

References

Dedek

Kunath

Kananura

Reuner

Jentsch

Steinlein

. Myokymia and neonatal epilepsy caused by a mutation in the voltage sensor of the KCNQ2 K+ channel. Proc Natl Acad Sci U S A. 2001;98:12272–12277.

Wuttke

Jurkat-Rott

Paulus

Garncarek

Lehmann-Horn

Lerche

. Peripheral nerve hyperexcitability due to dominant-negative KCNQ2 mutations. Neurology. 2007;69:2045–2053.

Grinton

Heron

Pelekanos

. Familial neonatal seizures in 36 families: clinical and genetic features correlate with outcome. Epilepsia. 2015;56:1071–1080.

Weckhuysen

Ivanovic

Hendrickx

. Extending the KCNQ2 encephalopathy spectrum: clinical and neuroimaging findings in 17 patients. Neurology. 2013;81:1697–1703.

Weckhuysen

Mandelstam

Suls

. KCNQ2 encephalopathy: emerging phenotype of a neonatal epileptic encephalopathy. Ann Neurol. 2012;71:15–25.

Blumkin

Suls

Deconinck

. Neonatal seizures associated with a severe neonatal myoclonus like dyskinesia due to a familial KCNQ2 gene mutation. Eur J Paediatr Neurol. 2012;16:356–360.

Orhan

Bock

Schepers

. Dominant-negative effects of KCNQ2 mutations are associated with epileptic encephalopathy. Ann Neurol. 2014;75:382–394.

Pisano

Numis

Heavin

. Early and effective treatment of KCNQ2 encephalopathy. Epilepsia. 2015;56:685–691.

Erro

Bhatia

Espay

Striano

. The epileptic and nonepileptic spectrum of paroxysmal dyskinesias: channelopathies, synaptopathies, and transportopathies. Mov Disord. 2017;32:310–318.

Supplementary Material

Please find the following supplemental material available below.

For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.

For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.

0.00 MB

4.38 MB