Hemiconvulsion-hemiplegia syndrome in a patient with severe myoclonic epilepsy in infancy

Area of Science:

• Genetics
• Neurology
• Pediatric Epilepsy

Background:

• A 2-year-old girl presented with intractable epilepsy, including hemiconvulsions and myoclonus, unresponsive to antiepileptic drugs.
• The patient experienced rotavirus infection, leading to status epilepticus and persistent hemiclonic seizures.

Purpose of the Study:

• To investigate the genetic basis of severe epilepsy with neurological complications in a pediatric patient.
• To explore the potential link between SCN1A mutations and the development of hemiconvulsion-hemiplegia (HH) syndrome.

Main Methods:

• Clinical case reporting of a pediatric patient with refractory epilepsy and neurological sequelae.
• Neuroimaging to assess brain lesions and atrophy.
• Genetic analysis of the SCN1A gene.

Main Results:

• The patient developed left unilateral brain edema, cortical laminar necrosis, white matter lesions, and progressive left cerebral hemisphere atrophy.
• Residual right hemiparesis, mild intellectual disability, and recurrent myoclonic seizures were observed.
• A nonsense mutation (R1892X) in the SCN1A gene was identified.

Conclusions:

• The findings suggest a potential risk for patients with severe myoclonic epilepsy in infancy (SMEI) to develop hemiconvulsion-hemiplegia (HH) syndrome.
• SCN1A mutations warrant further investigation in patients diagnosed with HH syndrome, particularly those without overt SMEI features.