[Epilepsy and other phenotypic features of X-linked intellectual disability caused by the mutations in the KIAA2022...

To study the literature data and a series of our cases regarding the epilepsy clinic, electroencephalographic changes and other phenotypic features in X-linked intellectual disability (ID) caused by KIAA2022 mutations.

We analyzed the anamnesis of the disease, using medical records from different Russian medical organizations, as well as the results of the genealogical anamnesis, clinical, genetic, electroencephalographic (EEG) and neuroimaging (brain MRI ) examinations of 7 patients (5 girls and 2 boys aged 5 to 13 years) with a confirmed diagnosis of X-linked ID caused by KIAA2022 mutations, in whom the clinical picture of the underlying disease was combined with epilepsy.

The main common phenotypic features of patients with X-linked ID caused by the KIAA2022 mutations are mental retardation, lack of phrasal speech, motor developmental delay, and dysmorphism. The prominent epilepsy characteristics are myoclonic, atonic seizures with nods, flinches, body propulsions, atypical absences, and diffuse discharges «spike-polyspike-slow wave» on the EEG. No pathognomonic brain changes were found on MRI. In many cases, the absence of the effect of antiepileptic therapy was noted.

The described cases of X-linked ID in combination with epilepsy show that this disease can be seen in males as well as in females, epilepsy is rather characterized by generalized seizures, and it is pharmacoresistant in many cases. There is a need for further research on this rare genetic syndrome.