Management of ring chromosome 20 syndrome: Narrative review and consensus recommendations

Ring chromosome 20 (ring 20) is a rare genetic condition usually presenting as developmental and epileptic encephalopathy. The disease is caused by fusion of the long and short arms of chromosome 20. Patients are symptomatic even if there is no loss of genetic material. Epilepsy in ring 20 is usually drug-resistant, with seizures often significantly debilitating and severely impacting quality of life. We assembled a taskforce of clinician-scientists with expertise in ring 20, as well as caregivers of individuals with ring 20. We then reviewed published literature on ring 20 with a focus on management with the aim of developing recommendations for the treatment of this disorder. Our review found that there are very few high-quality data available to guide treatment in ring 20. The majority of publications are individual case reports or small case series. Based on these limited data, as well as personal experience, we recommend the following. (1) The care team should be multidisciplinary and include at least an epileptologist and allied health specialists (e.g., speech therapist, occupational therapist, physiotherapist, psychologist); (2) patients and families should be referred for genetic counseling; (3) if patients are diagnosed with epilepsy, they and their families should be counseled that seizures are likely to be drug-resistant and life-long; (4) as there is a high incidence of non-convulsive status epilepticus (NCSE), there should be a low threshold for video-EEG monitoring if patients have a change in behavior or level of consciousness; (5) initial epilepsy treatment should be with an oral anti-seizure medication; (6) home rescue medication should be considered given the risk for prolonged seizures and NCSE; (7) for patients with drug-resistant epilepsy, ketogenic diet, vagus nerve stimulation, or deep brain stimulation could all be considered; and (8) caregiver burnout and stress should be screened for and supports provided.