A 5‐year‐old boy with super‐refractory status epilepticus and RANBP2 variant warranting life‐saving hemispherotomy

Abstract

Abstract Focal cortical dysplasia (FCD) represents the most common cause of drug‐resistant epilepsy in adult and pediatric surgical series. However, genetic factors contributing to severe phenotypes of FCD remain unknown. We present a patient with an exceptionally rapid development of drug‐resistant epilepsy evolving in super‐refractory status epilepticus. We performed multiple clinical (serial EEG, MRI), biochemical (metabolic and immunological screening), genetic (WES from blood‐ and brain‐derived DNA), and histopathological investigations. The patient presented 1 month after an uncomplicated varicella infection. MRI was negative, as well as other biochemical and immunological examinations. Whole‐exome sequencing of blood‐derived DNA detected a heterozygous paternally inherited variant NM_006267.4(RANBP2):c.5233A>G p.(Ile1745Val) (Chr2[GRCh37]:g.109382228A>G), a gene associated with a susceptibility to infection‐induced acute necrotizing encephalopathy. No combination of anti‐seizure medication led to a sustained seizure freedom and the patient warranted induction of propofol anesthesia with high‐dose intravenous midazolam and continuous respiratory support that however failed to abort seizure activity. Brain biopsy revealed FCD type IIa; this finding led to the indication of an emergency right‐sided hemispherotomy that rendered the patient temporarily seizure‐free. Postsurgically, he remains on antiseizure medication and experiences rare nondisabling seizures. This report highlights a uniquely severe clinical course of FCD putatively modified by the RANBP2 variant. Plain Language Summary We report a case summary of a patient who came to our attention for epilepsy that could not be controlled with medication. His clinical course progressed rapidly to life‐threatening status epilepticus with other unusual neurological findings. Therefore, we decided to surgically remove a piece of brain tissue in order to clarify the diagnosis that showed features of a structural brain abnormality associated with severe epilepsy, the focal cortical dysplasia. Later, a genetic variant in a gene associated with another condition, was found, and we hypothesize that this genetic variant could have contributed to this severe clinical course of our patient.

Keywords

• epilepsy surgery
• focal cortical dysplasia
• hemispherotomy
• RANBP2
• refractory status epilepticus