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.