Successful Hemispherotomy in a Patient With 22q11.2 Deletion Syndrome Who Had Developmental and Epileptic Encephalopathy With Spike-and-Wave Activation During Sleep.

We report a case of developmental and epileptic encephalopathy with spike-and-wave activation during sleep with 22q11.2 deletion syndrome in a patient who had undergone hemispherotomy and achieved developmental improvement. A four-year-old male child with paralysis on the left side of his body since birth had a mild developmental delay. An MRI of the brain revealed polymicrogyria diffusely throughout the right hemisphere. He was diagnosed with the 22q11.2 deletion syndrome at one year of age. Focal impaired awareness seizure in the right hemisphere origin and focal to bilateral tonic-clonic seizure appeared by two years of age. At three years of age, myoclonic seizures occurred, which induced frequent falls. Simultaneously, developmental and epileptic encephalopathy with spike-and-wave activation during sleep were observed. At four years and seven months of age, the patient underwent a right hemispherotomy. Epileptic seizures and spike-and-wave activation during sleep disappeared, and cognitive improvement was observed one year after surgery. In spite of chromosomal abnormalities being present, drug-resistant epilepsy with localized regions on MRI should be evaluated to determine surgical options to improve cognitive function and development.