Hemiconvulsion-hemiplegia-epilepsy syndrome with 5q33.3q34 microdeletion: Causal or chance association

Hemiconvulsion-hemiplegia-epilepsy (HHE) syndrome is a rare syndrome characterized by childhood onset partial motor convulsions, hemiplegia, and epilepsy in sequence. We presented a girl with global developmental delay with history and brain MRI consistent with the diagnosis of HHE syndrome. The cytogenetic microarray (CMA) showed 9.1 Mb deletion in 5q33.3q34 region. Along with HHE syndrome, the patient also had global developmental delay. Clinical phenotype of this microdeletion region has not been described in association with HHE syndrome in the literature. We compared the patient's phenotype with other patients in previously published papers of a common region of deletion spanning 157501989-164166203. GABRA1, GABRB2, GABRG2, CYFIP2, and THG1 are the important genes in the present deleted region, which may be responsible for the fever sensitivity and global developmental delay. This is the first case of HHE syndrome in which CMA showed a microdeletion of 5q33.3q34 region. This case report links HHE syndrome and global developmental delay to microdeletion of 5q33.3q34, which has never been reported in literature. The cause of HHE syndrome remains unexplained in present case and HHE may be a causal or chance co-occurrence.