INTRACTABLE EPILEPSY IN A PATIENT WITH 2Q34–24.3 DELETION

Objectives: Review of a 22 month old patient with a 2q23–24.3 deletion, with intractable epilepsy. Eight genes, which are putatively linked to seizure disorders, are encoded within this region.

Methods: Case report.

Results: Diagnosis of a 2q23q24.3 deletion was made when she presented at birth with an ASD/VSD, microstomia and ptosis. EEG and neurological examination were initially unremarkable. She developed focal onset seizures at 3 months that were resistant to oxcarbazepine, phenytoin, topiramate, pyridoxine and the ketogenic diet. A partial response has been achieved with high dose phenobarbital, clonazepam and stiripentol. She currently has clusters of partial and secondarily generalized seizures every 1–3 week, triggered by hyperthermia. More recently, she has developed profound ictal related central apnea. Her EEGs have poor background regionalization and multifocal epileptiform discharges. Recorded seizures have arisen from either temporal lobe, as well as the central regions. She remains hypotonic, and profoundly delayed with static development. Her MRI was normal and ABRs showed severe peripheral auditory conduction abnormalities.

Conclusion: This is a case of a rare genetic disorder involving deletion of a chromosomal region (2q23–24.3). This region encodes for 30 registered genes (OMIM), 11 that are involved in neuronal disorders, of which 8 have implied association with seizure disorders. Specifically, this region codes for sodium (5: including SCN1A), potassium (1), and calcium (1) channels, as well as the gene for benign familial infantile convulsions. The age of seizure onset, predisposition to hyperthermia and recurrent seizure clusters suggest a similarity to Dravet's syndrome; an intractable childhood epilepsy due to an SCN1A abnormality. However the epilepsy associated with this 2q23–24.3 deletion appears even more severe, as she has achieved only a partial response to therapies felt to be partially effective for Dravet's syndrome.