Ring chromosome 20 syndrome – A rare chromosomal cause of refractory epilepsy in children

Genetic disorders and chromosomal abnormalities have been shown to represent 2–3% of all cases of epilepsy. Ring chromosome 20 syndrome is a rare chromosomal abnormality and a rare cause of intractable epilepsy. Exact prevalence of ring chromosome 20 is not known. We report a case of a 10-year old boy who had had intractable epilepsy since 2 years of age. Birth history was insignificant and there was no obvious dysmorphism. His motor milestones were normal but cognition and speech were delayed. Electroencephalography showed progressive worsening from initial bi-frontal epileptiform activity to generalized discharges. Neuroimaging and metabolic work up was normal. Karyotype study showed ring chromosome 20. Diagnosis of ring chromosome 20 or r(20) syndrome was made. Ring chromosome 20 syndrome is a rare cause of refractory epilepsy A patient who present with intractable epilepsy with frontal epileptiform discharges, mental developmental delay, without dysmorphic features should be suspected of chromosomal abnormalities especially ring chromosome 20.