RARE DISEASE
GNAO1-related developmental delay-seizures-movement disorder spectrum
GNAO1-related developmental delay-seizures-movement disorder spectrum
GNAO1-related developmental delay-seizures-movement disorder spectrum
Synonyms: GNAO1-related neurodevelopmental disorder, GNAO1-related spectrum
Synonyms: GNAO1-related neurodevelopmental disorder, GNAO1-related spectrum
Synonyms: GNAO1-related neurodevelopmental disorder, GNAO1-related spectrum
Drug discovery
0
drugs
With orphan designations
Overview
GNAO1-related developmental delay-seizures-movement disorder spectrum is a rare neurodevelopmental condition caused by de novo pathogenic variants in the GNAO1 gene. It presents with hypotonia, global developmental delay, intellectual disability, and variable combinations of early-onset epilepsy (53% of cases) and severe movement disorders (89%), including dystonia, chorea, and life-threatening hyperkinetic crises. Neuroimaging may show cerebral atrophy or corpus callosum abnormalities. Mortality risk is elevated (5-26%) due to status dystonicus and respiratory complications [1][5][6][11].
Burden
High morbidity: 92% exhibit hypotonia, 100% have developmental delay, and 41% experience both seizures and movement disorders. Mortality reaches 26% in severe cases, driven by status dystonicus or respiratory failure [1][5][6]. Most patients are non-verbal, require wheelchair use, and incur significant caregiver stress [12][17].
Therapies
Movement disorders: Tetrabenazine, benzodiazepines, and deep brain stimulation (DBS) for refractory cases [3][5][11].
Epilepsy: GABAergic medications (e.g., carbamazepine, phenobarbital), though responses vary [1][12].
Supportive care: Tracheostomies, gastrostomy tubes, and multidisciplinary rehabilitation common [5][11].
Categories: rare genetic diseases, rare neurological diseases
Research Papers
30 drug discovery papers about GNAO1-related developmental delay-seizures-movement disorder spectrum, with 1 first-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
30 drug discovery papers about GNAO1-related developmental delay-seizures-movement disorder spectrum, with 1 first-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
categories:
Small molecules
small molecules
2026-09-11 | Novel and Emerging Therapies for Childhood‐Onset Movement Disorders
Childhood-onset movement disorders comprise a heterogeneous group of rare conditions with substantial unmet therapeutic needs. Recent advances in disease gene discovery, mechanistic modeling, and translational platforms have accelerated the development of targeted therapies and enabled innovative clinical trial designs for small patient populations. To review novel and emerging therapies for childhood-onset movement disorders, with a focus on pharmacologic strategies, disease-modifying approaches, and patient-centered precision therapies. We surveyed the literature, major conference proceedings, and expert networks to identify therapies approved, in clinical development, or supported by compelling preclinical data between 2022 and 2025. We focused on small molecules and genetic therapies for conditions in which movement disorders represent a prominent clinical feature. Small molecules were categorized as repurposed or novel drugs, whereas genetic therapies included gene replacement, gene editing, and RNA-based expression modulation. Drug repurposing approaches have shown promise in disorders related to the GNAO1, ATP1A3, ATM, and ADCY5 genes. Novel small molecules have advanced for Friedreich's ataxia and Tourette's syndrome. Gene replacement therapies have demonstrated clinical benefit in select neurotransmitter disorders, whereas gene editing strategies have entered preclinical development for ATP1A3-related disease. Antisense oligonucleotide therapies have yielded encouraging early results across several conditions with prominent movement disorder phenotypes, including KIF1A-related neurological disorder, Angelman syndrome, SCN2A-related neurodevelopmental disorder, and ataxia-telangiectasia. Precision-based therapeutic strategies are rapidly reshaping the treatment landscape for childhood-onset movement disorders. Continued progress will depend on rigorous phenotyping, careful ethical oversight, and deliberate efforts to promote equitable global access to emerging therapies. © 2026 International Parkinson and Movement Disorder Society.
2026-08-02 | Safety and feasibility of oral zinc for patients with GNAO1-related disorders (ZINCGNAO1): an open-label, single-arm, single-centre, pilot trial in Germany.
GNAO1-related disorders (GNAO1-RD), caused by variants in GNAO1 encoding the Gαo protein, comprise a broad phenotypic spectrum including movement disorders (MD) and/or epilepsy and are typically associated with developmental delay and intellectual disability. Currently, only symptomatic treatments are available. Zinc can restore guanosine triphosphate hydrolysis and cellular interactions of dysfunctional Gαo. ZINCGNAO1 evaluated the safety and feasibility of oral zinc supplementation in GNAO1-RD. ZINCGNAO1 was a 6-month, open-label, fixed-dose, single-centre pilot trial in Germany. Eligible participants were aged 6 months to 30 years, had a genetically confirmed GNAO1 variant, at least one hallmark feature of GNAO1-RD (MD, hypotonia, epilepsy, or global developmental delay), and had a Gross Motor Function Measure-66 (GMFM-66) score of 75 or lower. Zinc acetate dihydrate was administered orally in age-dependent dosages. Primary outcomes were safety, assessed by adverse event monitoring and laboratory analyses, and feasibility, defined as treatment adherence of at least 80% of days. Exploratory secondary outcomes included changes in MD severity (Burke-Fahn-Marsden Dystonia Rating Scale-Movement Score, BFMDRS-M, Abnormal involuntary movement scale, AIMS), and related disability (BFMDRS-Disability Score), motor function (GMFM-66), quality of life (Caregiver Priorities and Child Health Index of Life with Disabilities, CPCHILD), occupational performance (Canadian Occupational Performance Measure performance and satisfaction scores, COPM-P/-S), epilepsy, and participant- or caregiver-reported outcomes. This trial was registered at ClinicalTrials.gov (NCT06412653) and the EU Clinical Trials Register (2024-512735-72-00) and is complete. Between Aug 2, 2024, and Jan 27, 2025, 13 participants with 11 different genetic variants were enrolled; 11 completed the follow up of the trial. Mean age at inclusion was 8.0 years (range 0.5-25.1). Overall treatment feasibility was 84.6% (11/13). No treatment-related serious adverse events occurred, and laboratory monitoring did not identify clinically relevant safety concerns during the 6-month treatment period. Exploratory secondary outcomes showed no change in MD severity. The mean BFMDRS Disability Score decreased from 25.5 (SD 2.6) to 23.5 (SD 2.8; nominal p = 0.005). Mean GMFM-66 increased from 33.1 (SD 12.8) to 37.8 (SD 12.8, nominal p = 0.006). COPM-P increased from 2.6 (SD 0.8) to 3.8 (SD 1.3; nominal p = 0.003), and COPM-S from 2.7 (SD 0.9) to 4.1 (SD 1.7; nominal p = 0.002). CPCHILD and seizure occurrence showed no clear treatment-related change; two participants had seizures during the trial. Our preliminary findings show that oral zinc supplementation was safe and feasible in this GNAO1-RD population. Exploratory secondary outcomes suggested possible improvements in motor function and daily activities. Larger controlled trials are needed to assess efficacy. GNAO1-Gemeinsam nicht allein e.V.
2026-05-27 | Dissecting GPCR Contributions to Gαo-Dependent Motor Dysfunction in GNAO1-Related Disorders Using Caenorhabditis elegans.
Background/Objectives: Pathogenic variants in GNAO1, encoding the inhibitory G protein subunit Gαo, cause severe neurodevelopmental disorders that remain largely refractory to pharmacological treatments. Gαo transduces inhibitory signals downstream of multiple G protein-coupled receptors (GPCRs) involved in motor control. Here, we used gene-edited Caenorhabditis elegans models carrying goa-1 variants, the ortholog of GNAO1, to investigate GPCR contributions to Gαo-dependent locomotor phenotypes. Methods: We combined pharmacological screening of dopamine- and cannabinoid-targeting ligands in goa-1 mutants with structural analysis of ligand-binding pocket conservation and genetic perturbation of receptor function using RNAi and knockout approaches. Results: Pharmacological modulation of GPCR signaling produced non-linear and context-dependent effects. Compounds predicted to further increase excitability may instead promote phenotypic improvement, consistent with compensatory network rebalancing. Structural analyses revealed substantial divergence in ligand-binding pocket conservation for several GPCR-ligand pairs, suggesting that altered binding affinity and selectivity may also contribute to the observed phenotypic outcome. Pharmacological experiments performed in GPCR-depleted mutants allowed for the correlation of structural findings with functional effects for selected receptor-ligand pairs. Finally, genetic reduction in GPCRs coupled to stimulatory G proteins ameliorated hyperactive locomotion in goa-1 mutants, whereas reduction in GPCRs coupled to inhibitory G proteins is largely insufficient to induce or exacerbate locomotor defects. Conclusions: Our findings identify excessive excitatory GPCR input as a key modulator of motor dysfunction in the context of impaired Gαo signaling. They also show that structural conservation is a necessary but not sufficient condition to predict functional responses. Overall, this study establishes C. elegans as a suitable platform to dissect GPCR-mediated signaling and highlights the value of integrating pharmacological and genetic approaches to guide target selection in GNAO1-related disorders.
2026-04-23 | Small-molecule inhibitor of Gαo for GNAO1 encephalopathy.
GNAO1-related neurodevelopmental disorders are caused by mutations in the GNAO1 gene encoding the major neuronal G protein, Gαo. GNAO1 encephalopathies manifest in a range of symptoms, including epilepsy, movement disorder, hypotonia, and developmental delay, affecting >400 patients worldwide to date. A growth in the number of diagnosed cases is expected due to the wider availability of whole genome sequencing. One of the most recurrent pathogenic variants causing GNAO1 encephalopathy is an intronic mutation c.724-8G>A, which results in an in-frame insertion of two amino acid residues, Pro-Gln, after Thr241: Gαo[T241_N242insPQ]. We previously performed in-depth profiling of Gαo[insPQ] using structural, biochemical, and cellular studies. Compared with the wild-type protein, Gαo[insPQ] exhibits faster GTP binding and decreased hydrolysis. Importantly, Gαo[insPQ] is deficient in interacting with regulator of G protein signaling (RGS), GTPase-activating proteins that deactivate Gαo. These defects render Gαo[insPQ] a constitutively active mutant loaded with GTP in the G protein signaling. Patients harboring Gαo[insPQ] variant are in urgent need of novel therapy as they are refractory to available medications. In the present study, we performed a high-throughput screening to find molecules that might suppress the constitutive GTP loading by Gαo[insPQ]. We used a high-diversity chemical library of 54080 compounds, identifying a novel compound, N-[5-(2-methylpropyl)-1,3,4-thiadiazol-2-yl]-1H-1,2,3-benzotriazole-5-carboxamide, that decreases the GTP binding rate of Gαo, likely acting as a competitive inhibitor with higher selectivity to the pathogenic protein. This small-molecule inhibitor of Gαo opens new opportunities to drug discovery towards Gαo-dependent pathologies.
2026-03-28 | Conditional Modeling of GNAO1 Disorder Dissociates Circuit Specific Contributions to Pathology and Rationalizes Ameliorative Strategies
BACKGROUND: Neurodevelopmental disorders feature various symptoms that frequently include seizures and motor manifestations, but their attribution to disruptions of specific circuits and molecular alterations is notoriously hard to establish, which limits therapeutic interventions. Among these, is the GNAO1 disorder a severe pediatric encephalopathy associated with mutations in a gene encoding G protein subunit Gαo, a key transducer of neuromodulatory responses mediated by a vast number of G protein-coupled receptors. METHODS: In this study, we introduce a unique approach to modeling GNAO1 disorder, and neurodevelopmental disorders in general, by creating a conditional knock-in mouse model of a severe dominant negative GNAO1 variant G203R that allows circuit-specific induction of the mutation. A comprehensive battery of behavioral tests, together with electrophysiological recordings and proteomic analysis, was used to assess motor performance, seizure susceptibility, as well as molecular and functional alterations associated with the disorder. RESULTS: The model allowed parsing out circuit-specific contributions of Gαo dysfunction to motor and epileptic manifestations across neurons in striatum and forebrain. We further established molecular profiles of the disorder in a region-specific manner and documented the impact on synaptic transmission. This information guided the development of an intervention strategy using caffeine, which effectively rescued motor abnormalities. CONCLUSIONS: Our results point to the essential role of Gαo in maintaining neural circuit homeostasis. This advances our understanding of GNAO1 disorder-related disease mechanisms and lays foundation for rational, circuit-based therapeutic strategies. © 2026 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
oligonucleotides
2023-04-03 | CRISPR/Cas9-generated mouse model with humanizing single-base substitution in the Gnao1 for safety studies of RNA therapeutics
The development of personalized medicine for genetic diseases requires preclinical testing in the appropriate animal models. GNAO1 encephalopathy is a severe neurodevelopmental disorder caused by heterozygous de novo mutations in the GNAO1 gene. GNAO1 c.607 G>A is one of the most common pathogenic variants, and the mutant protein Gαo-G203R likely adversely affects neuronal signaling. As an innovative approach, sequence-specific RNA-based therapeutics such as antisense oligonucleotides or effectors of RNA interference are potentially applicable for selective suppression of the mutant GNAO1 transcript. While in vitro validation can be performed in patient-derived cells, a humanized mouse model to rule out the safety of RNA therapeutics is currently lacking. In the present work, we employed CRISPR/Cas9 technology to introduce a single-base substitution into exon 6 of the Gnao1 to replace the murine Gly203-coding triplet (GGG) with the codon used in the human gene (GGA). We verified that genome-editing did not interfere with the Gnao1 mRNA or Gαo protein synthesis and did not alter localization of the protein in the brain structures. The analysis of blastocysts revealed the off-target activity of the CRISPR/Cas9 complexes; however, no modifications of the predicted off-target sites were detected in the founder mouse. Histological staining confirmed the absence of abnormal changes in the brain of genome-edited mice. The created mouse model with the "humanized" fragment of the endogenous Gnao1 is suitable to rule out unintended targeting of the wild-type allele by RNA therapeutics directed at lowering GNAO1 c.607 G>A transcripts.
proteins
2025-06-22 | Visualizing the Dominant GPCR Coupling of Pathogenic Gαo Mutants in GNAO1 -Related Disorders
Abstract Heterozygous mutations in the GNAO1 gene, which encodes the Gαo subunit of heterotrimeric G proteins, cause a spectrum of rare neurodevelopmental disorders ranging from early-onset epileptic encephalopathy to milder dystonia phenotypes. Disease dominance of Gαo mutants appears to arise from multiple functional disruptions, including impaired guanine nucleotide handling, failure to adopt the active conformation, and neomorphic interactions with Ric8A/B chaperones. In parallel, several Gαo variants have been independently reported to dominantly engage G protein-coupled receptors (GPCRs) or to sequester Gβγ, two mechanistically distinct behaviors. These conclusions were inferred from different indirect biosensor assays, likely contributing to the apparent contradiction in their proposed mechanisms. To overcome this, we developed a split-YFP-based bimolecular fluorescence complementation (BiFC) assay to visualize receptor-Go protein complexes at the plasma membrane. Using this system, we found that severe Gαo variants (S47G, G203R, R209C, E246K) fail to disengage from activated Gi/o-coupled GPCRs, thereby preventing downstream receptor phosphorylation and endocytosis. By contrast, milder dystonia-linked mutants (C215Y and T241_N242insPQ) showed near-normal receptor internalization and only minor phosphorylation defects. These findings establish dominant GPCR coupling as a molecular hallmark of severe GNAO1 -related disorders and point to split-YFP BiFC as a robust platform for probing mutant G protein behavior in genetic disease.
2024-06-14 | Neomorphic Gαo mutations gain interaction with Ric8 proteins in GNAO1 encephalopathies
GNAO1 mutated in pediatric encephalopathies encodes the major neuronal G-protein Gαo. Of >80 pathogenic mutations, most are single amino acid substitutions spreading across Gαo sequence. We perform extensive characterization of Gαo mutants showing abnormal GTP uptake and hydrolysis, and deficiencies to bind Gβγ and RGS19. Plasma membrane localization of Gαo is decreased for a subset of mutations that leads to epilepsy; dominant interactions with GPCRs also emerge for the more severe mutants. Pathogenic mutants massively gain interaction with Ric8A and, surprisingly, Ric8B proteins, delocalizing them from cytoplasm to Golgi. Of these two mandatory Gα-subunit chaperones, Ric8A is normally responsible for the Gαi/o, Gαq, and Gα12/13 subfamilies, and Ric8B solely for Gαs/olf. Ric8A/B mediate the disease dominance when engaging in neomorphic interactions with pathogenic Gαo through disbalancing the neuronal G protein signaling networks. As the strength of Gαo-Ric8B interactions correlates with disease severity, our study further identifies an efficient biomarker and predictor for clinical manifestations in GNAO1 encephalopathies. Our work discovers the neomorphic molecular mechanism of mutations underlying pediatric encephalopathies and offers insights to other maladies caused by G protein misfunctioning and further genetic diseases.
small molecules
2026-09-11 | Novel and Emerging Therapies for Childhood‐Onset Movement Disorders
Childhood-onset movement disorders comprise a heterogeneous group of rare conditions with substantial unmet therapeutic needs. Recent advances in disease gene discovery, mechanistic modeling, and translational platforms have accelerated the development of targeted therapies and enabled innovative clinical trial designs for small patient populations. To review novel and emerging therapies for childhood-onset movement disorders, with a focus on pharmacologic strategies, disease-modifying approaches, and patient-centered precision therapies. We surveyed the literature, major conference proceedings, and expert networks to identify therapies approved, in clinical development, or supported by compelling preclinical data between 2022 and 2025. We focused on small molecules and genetic therapies for conditions in which movement disorders represent a prominent clinical feature. Small molecules were categorized as repurposed or novel drugs, whereas genetic therapies included gene replacement, gene editing, and RNA-based expression modulation. Drug repurposing approaches have shown promise in disorders related to the GNAO1, ATP1A3, ATM, and ADCY5 genes. Novel small molecules have advanced for Friedreich's ataxia and Tourette's syndrome. Gene replacement therapies have demonstrated clinical benefit in select neurotransmitter disorders, whereas gene editing strategies have entered preclinical development for ATP1A3-related disease. Antisense oligonucleotide therapies have yielded encouraging early results across several conditions with prominent movement disorder phenotypes, including KIF1A-related neurological disorder, Angelman syndrome, SCN2A-related neurodevelopmental disorder, and ataxia-telangiectasia. Precision-based therapeutic strategies are rapidly reshaping the treatment landscape for childhood-onset movement disorders. Continued progress will depend on rigorous phenotyping, careful ethical oversight, and deliberate efforts to promote equitable global access to emerging therapies. © 2026 International Parkinson and Movement Disorder Society.
2026-08-02 | Safety and feasibility of oral zinc for patients with GNAO1-related disorders (ZINCGNAO1): an open-label, single-arm, single-centre, pilot trial in Germany.
GNAO1-related disorders (GNAO1-RD), caused by variants in GNAO1 encoding the Gαo protein, comprise a broad phenotypic spectrum including movement disorders (MD) and/or epilepsy and are typically associated with developmental delay and intellectual disability. Currently, only symptomatic treatments are available. Zinc can restore guanosine triphosphate hydrolysis and cellular interactions of dysfunctional Gαo. ZINCGNAO1 evaluated the safety and feasibility of oral zinc supplementation in GNAO1-RD. ZINCGNAO1 was a 6-month, open-label, fixed-dose, single-centre pilot trial in Germany. Eligible participants were aged 6 months to 30 years, had a genetically confirmed GNAO1 variant, at least one hallmark feature of GNAO1-RD (MD, hypotonia, epilepsy, or global developmental delay), and had a Gross Motor Function Measure-66 (GMFM-66) score of 75 or lower. Zinc acetate dihydrate was administered orally in age-dependent dosages. Primary outcomes were safety, assessed by adverse event monitoring and laboratory analyses, and feasibility, defined as treatment adherence of at least 80% of days. Exploratory secondary outcomes included changes in MD severity (Burke-Fahn-Marsden Dystonia Rating Scale-Movement Score, BFMDRS-M, Abnormal involuntary movement scale, AIMS), and related disability (BFMDRS-Disability Score), motor function (GMFM-66), quality of life (Caregiver Priorities and Child Health Index of Life with Disabilities, CPCHILD), occupational performance (Canadian Occupational Performance Measure performance and satisfaction scores, COPM-P/-S), epilepsy, and participant- or caregiver-reported outcomes. This trial was registered at ClinicalTrials.gov (NCT06412653) and the EU Clinical Trials Register (2024-512735-72-00) and is complete. Between Aug 2, 2024, and Jan 27, 2025, 13 participants with 11 different genetic variants were enrolled; 11 completed the follow up of the trial. Mean age at inclusion was 8.0 years (range 0.5-25.1). Overall treatment feasibility was 84.6% (11/13). No treatment-related serious adverse events occurred, and laboratory monitoring did not identify clinically relevant safety concerns during the 6-month treatment period. Exploratory secondary outcomes showed no change in MD severity. The mean BFMDRS Disability Score decreased from 25.5 (SD 2.6) to 23.5 (SD 2.8; nominal p = 0.005). Mean GMFM-66 increased from 33.1 (SD 12.8) to 37.8 (SD 12.8, nominal p = 0.006). COPM-P increased from 2.6 (SD 0.8) to 3.8 (SD 1.3; nominal p = 0.003), and COPM-S from 2.7 (SD 0.9) to 4.1 (SD 1.7; nominal p = 0.002). CPCHILD and seizure occurrence showed no clear treatment-related change; two participants had seizures during the trial. Our preliminary findings show that oral zinc supplementation was safe and feasible in this GNAO1-RD population. Exploratory secondary outcomes suggested possible improvements in motor function and daily activities. Larger controlled trials are needed to assess efficacy. GNAO1-Gemeinsam nicht allein e.V.
2026-05-27 | Dissecting GPCR Contributions to Gαo-Dependent Motor Dysfunction in GNAO1-Related Disorders Using Caenorhabditis elegans.
Background/Objectives: Pathogenic variants in GNAO1, encoding the inhibitory G protein subunit Gαo, cause severe neurodevelopmental disorders that remain largely refractory to pharmacological treatments. Gαo transduces inhibitory signals downstream of multiple G protein-coupled receptors (GPCRs) involved in motor control. Here, we used gene-edited Caenorhabditis elegans models carrying goa-1 variants, the ortholog of GNAO1, to investigate GPCR contributions to Gαo-dependent locomotor phenotypes. Methods: We combined pharmacological screening of dopamine- and cannabinoid-targeting ligands in goa-1 mutants with structural analysis of ligand-binding pocket conservation and genetic perturbation of receptor function using RNAi and knockout approaches. Results: Pharmacological modulation of GPCR signaling produced non-linear and context-dependent effects. Compounds predicted to further increase excitability may instead promote phenotypic improvement, consistent with compensatory network rebalancing. Structural analyses revealed substantial divergence in ligand-binding pocket conservation for several GPCR-ligand pairs, suggesting that altered binding affinity and selectivity may also contribute to the observed phenotypic outcome. Pharmacological experiments performed in GPCR-depleted mutants allowed for the correlation of structural findings with functional effects for selected receptor-ligand pairs. Finally, genetic reduction in GPCRs coupled to stimulatory G proteins ameliorated hyperactive locomotion in goa-1 mutants, whereas reduction in GPCRs coupled to inhibitory G proteins is largely insufficient to induce or exacerbate locomotor defects. Conclusions: Our findings identify excessive excitatory GPCR input as a key modulator of motor dysfunction in the context of impaired Gαo signaling. They also show that structural conservation is a necessary but not sufficient condition to predict functional responses. Overall, this study establishes C. elegans as a suitable platform to dissect GPCR-mediated signaling and highlights the value of integrating pharmacological and genetic approaches to guide target selection in GNAO1-related disorders.
2026-04-23 | Small-molecule inhibitor of Gαo for GNAO1 encephalopathy.
GNAO1-related neurodevelopmental disorders are caused by mutations in the GNAO1 gene encoding the major neuronal G protein, Gαo. GNAO1 encephalopathies manifest in a range of symptoms, including epilepsy, movement disorder, hypotonia, and developmental delay, affecting >400 patients worldwide to date. A growth in the number of diagnosed cases is expected due to the wider availability of whole genome sequencing. One of the most recurrent pathogenic variants causing GNAO1 encephalopathy is an intronic mutation c.724-8G>A, which results in an in-frame insertion of two amino acid residues, Pro-Gln, after Thr241: Gαo[T241_N242insPQ]. We previously performed in-depth profiling of Gαo[insPQ] using structural, biochemical, and cellular studies. Compared with the wild-type protein, Gαo[insPQ] exhibits faster GTP binding and decreased hydrolysis. Importantly, Gαo[insPQ] is deficient in interacting with regulator of G protein signaling (RGS), GTPase-activating proteins that deactivate Gαo. These defects render Gαo[insPQ] a constitutively active mutant loaded with GTP in the G protein signaling. Patients harboring Gαo[insPQ] variant are in urgent need of novel therapy as they are refractory to available medications. In the present study, we performed a high-throughput screening to find molecules that might suppress the constitutive GTP loading by Gαo[insPQ]. We used a high-diversity chemical library of 54080 compounds, identifying a novel compound, N-[5-(2-methylpropyl)-1,3,4-thiadiazol-2-yl]-1H-1,2,3-benzotriazole-5-carboxamide, that decreases the GTP binding rate of Gαo, likely acting as a competitive inhibitor with higher selectivity to the pathogenic protein. This small-molecule inhibitor of Gαo opens new opportunities to drug discovery towards Gαo-dependent pathologies.
2026-03-28 | Conditional Modeling of GNAO1 Disorder Dissociates Circuit Specific Contributions to Pathology and Rationalizes Ameliorative Strategies
BACKGROUND: Neurodevelopmental disorders feature various symptoms that frequently include seizures and motor manifestations, but their attribution to disruptions of specific circuits and molecular alterations is notoriously hard to establish, which limits therapeutic interventions. Among these, is the GNAO1 disorder a severe pediatric encephalopathy associated with mutations in a gene encoding G protein subunit Gαo, a key transducer of neuromodulatory responses mediated by a vast number of G protein-coupled receptors. METHODS: In this study, we introduce a unique approach to modeling GNAO1 disorder, and neurodevelopmental disorders in general, by creating a conditional knock-in mouse model of a severe dominant negative GNAO1 variant G203R that allows circuit-specific induction of the mutation. A comprehensive battery of behavioral tests, together with electrophysiological recordings and proteomic analysis, was used to assess motor performance, seizure susceptibility, as well as molecular and functional alterations associated with the disorder. RESULTS: The model allowed parsing out circuit-specific contributions of Gαo dysfunction to motor and epileptic manifestations across neurons in striatum and forebrain. We further established molecular profiles of the disorder in a region-specific manner and documented the impact on synaptic transmission. This information guided the development of an intervention strategy using caffeine, which effectively rescued motor abnormalities. CONCLUSIONS: Our results point to the essential role of Gαo in maintaining neural circuit homeostasis. This advances our understanding of GNAO1 disorder-related disease mechanisms and lays foundation for rational, circuit-based therapeutic strategies. © 2026 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
oligonucleotides
2023-04-03 | CRISPR/Cas9-generated mouse model with humanizing single-base substitution in the Gnao1 for safety studies of RNA therapeutics
The development of personalized medicine for genetic diseases requires preclinical testing in the appropriate animal models. GNAO1 encephalopathy is a severe neurodevelopmental disorder caused by heterozygous de novo mutations in the GNAO1 gene. GNAO1 c.607 G>A is one of the most common pathogenic variants, and the mutant protein Gαo-G203R likely adversely affects neuronal signaling. As an innovative approach, sequence-specific RNA-based therapeutics such as antisense oligonucleotides or effectors of RNA interference are potentially applicable for selective suppression of the mutant GNAO1 transcript. While in vitro validation can be performed in patient-derived cells, a humanized mouse model to rule out the safety of RNA therapeutics is currently lacking. In the present work, we employed CRISPR/Cas9 technology to introduce a single-base substitution into exon 6 of the Gnao1 to replace the murine Gly203-coding triplet (GGG) with the codon used in the human gene (GGA). We verified that genome-editing did not interfere with the Gnao1 mRNA or Gαo protein synthesis and did not alter localization of the protein in the brain structures. The analysis of blastocysts revealed the off-target activity of the CRISPR/Cas9 complexes; however, no modifications of the predicted off-target sites were detected in the founder mouse. Histological staining confirmed the absence of abnormal changes in the brain of genome-edited mice. The created mouse model with the "humanized" fragment of the endogenous Gnao1 is suitable to rule out unintended targeting of the wild-type allele by RNA therapeutics directed at lowering GNAO1 c.607 G>A transcripts.
proteins
2025-06-22 | Visualizing the Dominant GPCR Coupling of Pathogenic Gαo Mutants in GNAO1 -Related Disorders
Abstract Heterozygous mutations in the GNAO1 gene, which encodes the Gαo subunit of heterotrimeric G proteins, cause a spectrum of rare neurodevelopmental disorders ranging from early-onset epileptic encephalopathy to milder dystonia phenotypes. Disease dominance of Gαo mutants appears to arise from multiple functional disruptions, including impaired guanine nucleotide handling, failure to adopt the active conformation, and neomorphic interactions with Ric8A/B chaperones. In parallel, several Gαo variants have been independently reported to dominantly engage G protein-coupled receptors (GPCRs) or to sequester Gβγ, two mechanistically distinct behaviors. These conclusions were inferred from different indirect biosensor assays, likely contributing to the apparent contradiction in their proposed mechanisms. To overcome this, we developed a split-YFP-based bimolecular fluorescence complementation (BiFC) assay to visualize receptor-Go protein complexes at the plasma membrane. Using this system, we found that severe Gαo variants (S47G, G203R, R209C, E246K) fail to disengage from activated Gi/o-coupled GPCRs, thereby preventing downstream receptor phosphorylation and endocytosis. By contrast, milder dystonia-linked mutants (C215Y and T241_N242insPQ) showed near-normal receptor internalization and only minor phosphorylation defects. These findings establish dominant GPCR coupling as a molecular hallmark of severe GNAO1 -related disorders and point to split-YFP BiFC as a robust platform for probing mutant G protein behavior in genetic disease.
2024-06-14 | Neomorphic Gαo mutations gain interaction with Ric8 proteins in GNAO1 encephalopathies
GNAO1 mutated in pediatric encephalopathies encodes the major neuronal G-protein Gαo. Of >80 pathogenic mutations, most are single amino acid substitutions spreading across Gαo sequence. We perform extensive characterization of Gαo mutants showing abnormal GTP uptake and hydrolysis, and deficiencies to bind Gβγ and RGS19. Plasma membrane localization of Gαo is decreased for a subset of mutations that leads to epilepsy; dominant interactions with GPCRs also emerge for the more severe mutants. Pathogenic mutants massively gain interaction with Ric8A and, surprisingly, Ric8B proteins, delocalizing them from cytoplasm to Golgi. Of these two mandatory Gα-subunit chaperones, Ric8A is normally responsible for the Gαi/o, Gαq, and Gα12/13 subfamilies, and Ric8B solely for Gαs/olf. Ric8A/B mediate the disease dominance when engaging in neomorphic interactions with pathogenic Gαo through disbalancing the neuronal G protein signaling networks. As the strength of Gαo-Ric8B interactions correlates with disease severity, our study further identifies an efficient biomarker and predictor for clinical manifestations in GNAO1 encephalopathies. Our work discovers the neomorphic molecular mechanism of mutations underlying pediatric encephalopathies and offers insights to other maladies caused by G protein misfunctioning and further genetic diseases.
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