title: Neonatal seizures associated with a severe neonatal myoclonus like dyskinesia due to a familial KCNQ2 gene mutation.
abstract: Mutations in the potassium channel gene KCNQ2, usually cause benign familial neonatal epilepsy. This is an autosomal dominant disorder characterized by clusters of seizures occurring in the first days of life. Most patients have normal psychomotor development and spontaneous remission of seizures by 12 months of age. Since Rett and Teubel reported the first family in 1964 and the identification of KCNQ2 gene mutations in this family by Zimprich et al. in 2006, phenotypic variability has been recognized including: later onset of seizures, myokymia in isolation or accompanied by seizures, neurological deficit and mental retardation. We report a mother and son with an atypical presentation of familial neonatal epilepsy. The mother has persistent epilepsy and subnormal intelligence. The son developed a severe dyskinesia clinically compatible with multifocal myoclonus in the neonatal period that only responded to carbamazepine. He also has ataxia and delayed psychomotor development. EMG revealed a spontaneous occurrence of repetitive normal motor potentials in different muscle groups. Genetic analysis identified a heterozygous missense mutation in KCNQ2 in the child and his mother.
  
  
  CONCLUSIONS
  KCNQ2 mutations can present with a neonatal onset multifocal myoclonus-like dyskinesia.
authors.affiliation: Pediatric Neurology Unit, Wolfson Medical Center, Holon, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
authors.forename: Lubov
authors.initials: L
authors.lastname: Blumkin
authors.forename: Arvid
authors.initials: A
authors.lastname: Suls
authors.forename: Tine
authors.initials: T
authors.lastname: Deconinck
authors.forename: Peter
authors.initials: P
authors.lastname: De Jonghe
authors.forename: Ilan
authors.initials: I
authors.lastname: Linder
authors.forename: Sara
authors.initials: S
authors.lastname: Kivity
authors.forename: Ron
authors.initials: R
authors.lastname: Dabby
authors.forename: Esther
authors.initials: E
authors.lastname: Leshinsky-Silver
authors.forename: Dorit
authors.initials: D
authors.lastname: Lev
authors.forename: Tally
authors.initials: T
authors.lastname: Lerman-Sagie
mesh_terms: D000328:Adult; D000927:Anticonvulsants / Q000627:therapeutic use; D002220:Carbamazepine / Q000627:therapeutic use; D002658:Developmental Disabilities / Q000209:etiology; D020820:Dyskinesias / Q000150:complications* / Q000235:genetics*; D004569:Electroencephalography; D004576:Electromyography; D020936:Epilepsy, Benign Neonatal / Q000150:complications* / Q000235:genetics*; D005091:Exons / Q000235:genetics; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008607:Intellectual Disability / Q000150:complications; D007585:Jews; D051658:KCNQ2 Potassium Channel / Q000235:genetics*; D008297:Male; D009154:Mutation / Q000235:genetics / Q000502:physiology; D020125:Mutation, Missense / Q000235:genetics; D009207:Myoclonus / Q000150:complications* / Q000235:genetics*; D009460:Neurologic Examination; D011247:Pregnancy
chemical_list: D000927:Anticonvulsants; D051658:KCNQ2 Potassium Channel; C496914:KCNQ2 protein, human; D002220:Carbamazepine