Objectives. To assess published data and a series of clinical cases in relation to the clinical features of epilepsy, electroencephalographic changes, and other phenotypic features in X-linked intellectual disability (ID) caused by mutations in the KIAA2022 gene. Materials and methods. Retrospective analysis of medical records from various medical institutions of the Russian Federation was conducted, addressing disease and genealogical histories, , and clinical, genetic, electroencephalographic (EEG), and neuroimaging (brain MRI) investigations. The study included seven clinical cases (five girls and two boys, 5–13 years old) with confirmed diagnoses of X-linked ID due to mutations in KIAA2022 in whom the clinical picture of the underlying disease was combined with epilepsy. Results. The main general phenotypic characteristics of patients with X-linked ID due to KIAA2022 mutations were mental retardation, speech impairment, motor developmental delay, and dysmorphism. The most frequently encountered epileptic seizures were myoclonic and atonic, with nodding, propulsion, atypical absences, and EEG changes showing diffuse “spike– multispike–slow wave” complexes. No pathognomonic brain changes were found on MRI. Antiepileptic therapy was ineffective in many cases. Conclusions. The cases of X-linked ID combined with epilepsy described here indicate that this disease can occur both in males and females and that epilepsy is more often apparent as generalized seizures and in many cases is drug-resistant. More information is needed about this rare genetic syndrome.