Genetic generalized epilepsy in three siblings with 8q21.13-q22.2 duplication.

PURPOSE: Duplication of chromosome region 8q21-q22 is a rare copy number variant that has been previously reported in a limited number of patients. Although some of these patients had seizures, their electroclinical syndrome has not been described in detail. The aim of this study was to provide further insight into the specific epilepsy syndrome associated with 8q21.13-q22.2 duplication.

METHOD: We describe 3 siblings with trisomy of 8q21.13-q22.2 who exhibited intellectual disability, facial dysmorphism and seizures.

RESULTS: All of the patients responded satisfactorily to antiepileptic medication. The EEG showed typical 3-Hz generalized spike-and-wave interictal discharges. Microarray analyses revealed duplication of 8q21.13-q22.2, encompassing 10 OMIM morbid map genes. The analysis demonstrated that the parental origin of the additional copy of 8q22.13-q22.2 was maternal, translocated to chromosome 4p.

CONCLUSION: Our report supports that duplication of 8q21.13-q22.2 is associated with genetic generalized epilepsy with early onset absence and generalized tonic clonic seizures, in addition to the previously reported features of intellectual disability and dysmorphism.