CUL4B-associated epilepsy: Report of a novel truncating variant promoting drug-resistant seizures and systematic review of the literature

•43% of CUL4B patients develop seizures.•CUL4B-associated epilepsy may also be drug-resistant and persist beyond infancy.•Seizures can arise with different mutation types.•Neuroimaging features do not predict the development of epilepsy in CUL4B patients. : Cabezas syndrome is a rare X-linked disease caused by mutations in CUL4B and characterized by developmental delay/intellectual disability, somatic dysmorphisms, behavioural disorder, ataxia/tremors. Although seizures have been formerly reported, their clinical semiology, EEG features and long-term outcome are largely unknown. This study aims to expand knowledge on epilepsy associated with Cabezas syndrome and to understand whether different types of variants in the CUL4B gene or brain MRI abnormalities may influence seizure onset and epilepsy course. With this in mind, we characterised the epileptic phenotype of a 17-year-old adolescent harbouring a CUL4B novel variant and performed a systematic literature review of CUL4B-associated seizures, analysing mutation types and neuroimaging features as epilepsy predictors. Our case observation indicates that CUL4B-associated epilepsy may also be drug-resistant and persist beyond infancy. Literature analysis shows that 43% of CUL4B patients develop seizures, with no statistically significant differences in epilepsy development according to mutation type and neuroimaging features. Our study extends knowledge of CUL4B-associated epilepsy, offering new insights into disease progression.