SCN8A Epileptic Encephalopathy: Detection of Fetal Seizures Guides Multidisciplinary Approach to Diagnosis and Treatment

Pediatr Neurol. 2016 Nov;64:87-91. doi: 10.1016/j.pediatrneurol.2016.08.003. Epub 2016 Aug 16.

Abstract

Background: SCN8A mutations are rare and cause a phenotypically heterogeneous early onset epilepsy known as early infantile epileptic encephalopathy type 13 (EIEE13, OMIM #614558). There are currently no clear genotype-phenotype correlations to help guide patient counseling and management.

Patient description: We describe a patient with EIEE13 (de novo heterozygous pathogenic mutation in SCN8A - p.Ile240Val (ATT>GTT)) who presented prenatally with maternally reported intermittent, rhythmic movements that, when observed on ultrasound, were concerning for fetal seizures. Ultrasound also revealed abnormal developmental states. With maternal administration of levetiracetam, the rhythmic fetal movements stopped. After birth, the patient developed treatment-refractory multi-focal epilepsy confirmed by electroencephalogram. Neuroimaging revealed restricted diffusion in the superior cerebellar peduncles, a finding not reported previously in EIEE13.

Conclusion: This is the first report of EIEE13 associated with clinical prenatal-onset seizures. Ultrasonography can be useful for identifying fetal seizures, which may be treatable in utero. Ideally, the clinical approach to fetal seizures should involve a multidisciplinary team spanning the pre- and postnatal course to expedite early diagnosis and optimize management, as illustrated by this patient.

Keywords: SCN8A; arthrogryposis; early infantile epileptic encephalopathy; fetal seizures; sodium channels; ultrasonography.

Publication types

  • Case Reports

MeSH terms

  • Brain / diagnostic imaging
  • Brain / drug effects
  • Brain / embryology
  • Brain / physiopathology
  • Epilepsy / diagnosis*
  • Epilepsy / genetics
  • Epilepsy / physiopathology
  • Epilepsy / therapy*
  • Female
  • Fetal Diseases / diagnosis*
  • Fetal Diseases / genetics
  • Fetal Diseases / physiopathology
  • Fetal Diseases / therapy*
  • Humans
  • Infant, Newborn
  • NAV1.6 Voltage-Gated Sodium Channel / genetics*
  • Seizures / diagnosis
  • Seizures / genetics
  • Seizures / physiopathology
  • Seizures / therapy
  • Ultrasonography, Prenatal

Substances

  • NAV1.6 Voltage-Gated Sodium Channel
  • SCN8A protein, human