Epilepsy phenotypes of Renu syndrome: Novel insights from a European multicentre retrospective cohort study

Background Epilepsy is a prominent feature in about 60% of patients with ReNU syndrome Patients and methods Data including demographics, gene variants, seizure semiology and evolution, EEG patterns, neurodevelopmental features, MRI characteristics and response to antiseizure medications were retrospectively collected in a cohort of patients with ReNU syndrome referred to 6 European tertiary centres. Results The cohort included 10 patients (7 males and 3 females). The mean age at epilepsy onset was 2.8 ±2.1 years. No specific epilepsy syndromes were recognized. Focal impaired consciousness with observable manifestations (with onset before 12 months in 3 cases) were the predominant seizure type across all age ranges. The frequency of this seizure type peaked between the ages of 6 and 11 years. Generalized seizures were less common and mainly occurred under the age of 6 with a similar frequency of atypical absences and tonic/tonic clonic seizures. Interictal and ictal epileptiform EEG were more frequently detected after 3 years of age and were mainly focal (with predominant involvement of the fronto-parietal regions). No structural epileptogenic lesions were detected on MRI. Seizure freedom was achieved with antiseizure medications in 5 patients at a mean age of 7.2 ± 25.2. Valproate was judged the most effective medication by referring neurologists followed by levetiracetam, clobazam, lamotrigine and phenytoin. No relevant genotype-phenotype correlations were observed. Conclusions The phenotype of the seizure disorders observed in this cohort was dominated by focal impaired consciousness seizures with observable manifestations and a relatively favourable course of epilepsy.