A novel GABRG2 variant in Sunflower syndrome: A case report and video EEG monitoring.

OBJECTIVE

Sunflower syndrome is a unique photosensitive epilepsy, characterized by heliotropism and stereotyped seizures associated with handwaving. These handwaving events (HWE) are thought to be an ictal phenomenon, although current data are contrasting. Photosensitive epilepsy occurs in 2%-5% of the epilepsy forms and several pathogenic gene variants have been associated with photosensitive epilepsy. However, the genetic etiology of Sunflower syndrome remains unknown. Antiseizure medications (ASM) efficacious in treating photosensitive epilepsy are valproic acid (VPA) and levetiracetam (LEV) although some forms, such as Sunflower syndrome, can be drug-resistant.

METHODS AND RESULTS

Here, we report an 8-year-old boy with an early onset of episodes of HWE that was initially categorized as behavioral problems for which risperidone was started. However, the medical history was suggestive of Sunflower syndrome, and subsequent video EEG showed focal mostly temporal and frontotemporal (right and left) epileptiform activity and confirmed the epileptic nature of the HWE. Thus, VPA was started and initially led to seizure frequency reduction. Molecular analyses showed a pathogenic variant in GABRG2 (c.1287G>A p.(Trp429Ter)), which has been associated with photosensitive and generalized epilepsy.

SIGNIFICANCE

Overall, clinicians worldwide should be cautious by interpreting HWE and/or other tic-like movements, since an epileptic origin cannot be ruled out. A prompt and correct diagnosis can be made by performing a video EEG early on in the diagnostic process when epileptic seizures are part of the differential diagnosis. Even though the genetic etiology of Sunflower syndrome remains poorly understood, this constellation supports further genetic testing since the detection of a pathogenic variant can help in making correct decisions regarding ASM management.