The syndrome caused by mutations in the GABBR2 gene is characterized by epilepsy including epileptic encephalopathy, severe intellectual disability, and Rett-like phenotypes (RTT) with neurodevelopmental regression. Pathogenic GABBR2 variants are reported to occur de novo. The diagnosis is based on the symptoms with confirmatory genetic testing. As of 2021, only a handful of confirmed cases have been reported. Treatment for this syndrome is focused on managing the symptoms, such as epilepsy or developmental delays.