A novel GABRB3 variant in Dravet syndrome: Case report and literature review.

Background: Mutations in GABRB3 have been identified in subjects with different types of epilepsy and epileptic syndromes, including West syndrome (WS), Dravet syndrome (DS), Lennox-Gastaut syndrome (LGS), myoclonic-atonic epilepsy (MAE), and others.

Methods And Results: We herewith report on a girl affected by DS, who has been followed from infancy to the current age of 18 years. Next-generation sequencing (NGS)-based genetic testing for multigene analysis of neurodevelopmental disorders identified two likely de novo pathogenic mutations, a missense variant in GABRB3 gene (c.842 C>T; p.Thr281IIe) and a nonsense variant found in BBS4 gene (c.883 C>T; p.Arg295Ter).

Conclusion: A likely relationship between the novel GABRB3 gene variant and the clinical manifestations presented by the girl is proposed. Previously, one case of DS and two of DS-like linked with GABRB3 mutations have been reported. To the best of our knowledge, this is the first report of DS associated with this novel variant. A literature review of clinical cases with various types of epileptic encephalopathies (EEs) related to GABRB3 mutations is reported.