Personalized allele-specific antisense oligonucleotides for GNAO1-neurodevelopmental disorder

GNAO1-associated disorders are ultra-rare autosomal dominant conditions, which can manifest, depending on the exact pathogenic variant in <i>GNAO1</i>, as a spectrum of neurological phenotypes, including epileptic encephalopathy, developmental delay with movement disorders, or late-onset dystonia. There are currently no effective treatments available, apart from symptomatic options. In this work, we suggest harnessing personalized RNA therapy to treat <i>GNAO1</i> patients and focus specifically on a recurrent pathogenic variant (E246K). We systemically screened allele-specific antisense oligonucleotides (ASOs) targeting the mutated allele to identify a potent and specific sequence using both reporter-based platforms and a patient-derived cellular model. We show that reduction of mutated <i>GNAO1 in vitro</i> by knockout or by ASO has a beneficial functional outcome, which can be measured by cAMP accumulation and gene expression changes. We established a Gnao1-E246K mouse model that shows a neurological phenotype, which partially recapitulates the human condition. Due to sequence similarity, the mouse can be treated with the selected ASO to test treatment efficacy in animal models, as shown <i>in vitro</i> using murine neural progenitor cells. Our results demonstrate a beneficial effect for the reduction of mutated <i>GNAO1</i> by ASO in patient-derived models, demonstrating its feasibility as a therapeutic approach.