Electroclinical Improvement in a Patient with Ring Chromosome 20 Syndrome Treated with Zonisamide: A Case Report.

Ring chromosome 20 or r(20) syndrome is a rare chromosomal disorder, mainly characterized by childhood-onset drug-resistant epilepsy with typical electroencephalographic findings, followed by mild to severe cognitive-behavioral decline. Recent studies support a possible role of the dopaminergic system in the epileptogenesis of this syndrome. We report the case of a 13-year-old female with mosaic r(20) who showed typical disease onset and evolution and a remarkable electroclinical improvement with zonisamide. Epilepsy related to r(20) is often medically intractable. When valproate and lamotrigine are not effective, zonisamide could be further investigated as a therapeutic option, since it acts as antifocal and it has a potential role in the prevention of dopamine depletion.