Clinical Phenotype of De Novo <i>GNAO1</i> Mutation

Abstract

Mutations in the guanine nucleotide-binding protein (G protein), α activating activity polypeptide O (<i>GNAO1</i>) gene have recently been described in 6 patients with early infantile epileptic encephalopathies. In the present study, we report the phenotype and the clinical course of a 4-year-old female with an epileptic encephalopathy (Ohtahara syndrome) and profound intellectual disability due to a de novo <i>GNAO1</i> mutation (c.692A>G; p.Tyr231Cys). Ohtahara syndrome is a devastating early infantile epileptic encephalopathy that can be caused by mutations in different genes, now also including <i>GNAO1</i>. The mutation was found using a targeted next generation sequencing gene panel and demonstrates targeted sequencing as a powerful tool for identifying mutations in genes where only a few de novo mutations have been identified.