GNAO1-related Neurodevelopmental Disorder · GNAO1

What this is

GNAO1-related neurodevelopmental disorder is caused by heterozygous mutations in GNAO1, the gene encoding the alpha subunit of the heterotrimeric G-protein Go. Go is one of the most abundant G-proteins in the brain, where it couples to dopamine, GABA, and other neurotransmitter receptors and regulates intracellular signaling cascades that control neuronal excitability and synaptic transmission.

The clinical phenotype is variable and severity-graded by mutation. The most common presentations include severe developmental delay, profound intellectual disability, treatment-refractory epilepsy, and a movement disorder that often combines chorea, dystonia, and dyskinetic episodes. Some affected children experience life-threatening movement-disorder exacerbations that require intensive-care management. Other variants produce a more pure epileptic-encephalopathy phenotype without prominent movement features. Onset is typically in infancy.

The condition was first molecularly characterized in 2013 by Nakamura, Kodera, and colleagues, who identified de novo GNAO1 missense variants in children with epileptic encephalopathy. Subsequent work has identified roughly 400 affected individuals globally as of 2025, with the spectrum of phenotypes expanded as more cases have been recognized through clinical exome sequencing.

The mutations divide functionally into gain-of-function variants (which produce the more severe movement-disorder phenotype) and loss-of-function variants (which tend to produce the more pure epileptic encephalopathy presentation). The functional distinction matters for therapeutic strategy: gain-of-function variants are candidates for allele-selective knockdown approaches, while loss-of-function variants may require gene replacement or expression upregulation.

There is no approved disease-modifying therapy. Standard of care is anticonvulsant management, supportive care for the movement disorder, sometimes with deep-brain stimulation for severe dystonia or chorea, and intensive-care support during movement-disorder exacerbations. The disease is steadily progressive, though the trajectory is variable.

The case

The Bow Foundation was launched in April 2017 by two families, the Bell and Fox families, after their children were diagnosed with GNAO1-related disorders in 2016. Co-chairs Emily Bell and Alice Fox structured the foundation to address what they had encountered in the months following diagnosis: a condition the medical community had only just begun to recognize, no organized research or therapeutic-development pipeline, and no community of affected families to compare notes with.

Each founding family had one of the small number of affected children identified at that time globally. The Bell and Fox children, like most early-diagnosed GNAO1 cases, were identified through clinical exome or epilepsy-panel sequencing for unexplained early-life seizures and developmental delay. The diagnosis named the gene and the protein, but it produced no clinical-trial enrollment, no therapeutic option beyond standard supportive care, and no clear scientific basis for predicting which individual children would respond to which interventions.

The foundation's structure followed a model that had been developed in adjacent rare-disease communities. The two founding families incorporated a non-profit, identified a small initial cohort of additional families through clinician outreach and direct contact, established a patient registry to collect longitudinal natural-history data, and began funding small research grants to investigators willing to work on GNAO1 biology.

By 2024 the foundation had supported more than one million dollars in cumulative research funding, had identified over 400 affected individuals globally, and had begun to underwrite clinical research that the standard pharmaceutical pipeline would not have funded. The annual GNAO1 Conference, which the foundation convenes, brings together affected families, treating clinicians, and researchers; the 2024 conference reportedly drew families from Argentina, Italy, and across the United States.

The therapeutic program that has emerged most directly from the foundation's funding is a partnership with Jennifer Friedman, a movement-disorder specialist at the University of California San Diego and Rady Children's Hospital, and the n-Lorem Foundation. Friedman's program develops individualized antisense oligonucleotides for GNAO1 gain-of-function variants. The Bow Foundation funds the clinical observation work that runs alongside the n-Lorem-developed therapy: collecting baseline assessments, defining outcome measures specific to the GNAO1 movement disorder, and tracking longitudinal changes in treated and untreated affected children.

As of 2025, the first individual treated under the Friedman/n-Lorem partnership has begun receiving the experimental ASO. Clinical observations are being collected against the natural-history baseline the registry has established. The published report on outcomes is in preparation; the n-Lorem 2025 nano-rare patient colloquium referenced the GNAO1 program as one of the active treatments in the Foundation's pipeline.

The research

The therapeutic strategy for GNAO1 gain-of-function variants is conceptually similar to the strategy Wendy Chung's program used for KIF1A: an allele-selective antisense oligonucleotide designed to suppress the mutant GNAO1 transcript while preserving expression of the wild-type allele. The mechanism is RNase H-mediated cleavage of the mutant mRNA, with the sequence specificity achieved through careful ASO design around the missense variant site.

The chemistry class is the standard 2'-O-methoxyethyl phosphorothioate gapmer that the n-Lorem Foundation uses across its catalog. The intrathecal route is the same route used for milasen, atipeksen, valeriasen, the KIF1A program, and the broader n-Lorem and Boston Children's pipeline. The safety database for the chemistry class and the route is now substantial enough that GNAO1 programs can leverage the precedent without re-establishing the basic safety parameters from scratch.

The natural-history work the Bow Foundation has funded is the trial-readiness piece that the program has needed. GNAO1-related movement disorder is a heterogeneous condition without FDA-validated outcome measures, and the registry data the foundation has built provides the comparator dataset against which any treated patient's trajectory can be interpreted. The Friedman group at Rady Children's and the broader UCSD movement-disorder program contribute the clinical assessments and the academic-trial infrastructure.

Funding for the program comes from a combination of n-Lorem (which covers the development and manufacturing costs through philanthropic donations), the Bow Foundation (which covers clinical-research costs), and the Bell and Fox families and broader GNAO1 community (who have contributed both directly and through fundraising events).

The program is not the first GNAO1 therapeutic effort. Earlier published work has explored repurposing of caffeine and other small molecules for the movement-disorder phenotype, and several research groups have studied the biochemistry of GNAO1 mutations in cell-culture and animal models. The n-Lorem ASO program is the first individualized therapeutic to reach clinical evaluation.

What is blocking the next case

The structural blockers facing the GNAO1 field are similar to those facing the KIF1A field, with one important addition. The gain-of-function and loss-of-function distinction means that not every affected child can be addressed by the same therapeutic strategy. Children with gain-of-function variants are candidates for allele-selective knockdown like the Friedman/n-Lorem program. Children with loss-of-function variants would require a different approach, likely gene replacement or expression upregulation, neither of which has reached clinical evaluation.

The first blocker is variant-specific therapeutic design. An allele-selective ASO targeting one GNAO1 missense variant addresses approximately the population of children sharing that specific variant. Each new variant requires its own ASO design, validation, and IND submission. The Bow Foundation's identified cohort includes dozens of distinct variants, with most variants present in only one or a few affected children.

The second blocker is the dose sensitivity of the GNAO1 gene product. Go is a major neuronal G-protein, and both reduced and increased expression produce phenotypes. Allele-selective knockdown that succeeds in reducing the mutant protein without significantly reducing wild-type expression is technically achievable but requires careful design and verification.

The third blocker is the lack of disease-specific biomarkers. Cerebrospinal fluid neurofilament light chain, the biomarker that has been useful for FUS-ALS and several neurodegenerative ASO programs, is less informative for GNAO1 because the disease is primarily a synaptic-transmission disorder rather than a neurodegenerative one. Outcome measures for the movement disorder, the seizures, and the developmental phenotypes are being developed through the Friedman group's work but are not yet validated in the same way KIF1A or SLC6A1 outcome measures have been.

The fourth blocker is the same scaling problem that the broader n-Lorem ecosystem faces: small-batch GMP manufacturing capacity, regulatory bandwidth for a growing pipeline of similar but variant-specific INDs, and the philanthropic funding model that supports it.

Where this connects

The institutional model the GNAO1 program uses is the model described in Stanley Crooke and the n-of-many foundation, and the chemistry class is the class described in How splice-switching ASOs work (though the GNAO1 program uses the gapmer / RNase H mechanism rather than splice modulation). The natural-history-first methodology the Bow Foundation has built parallels the approach described in Wendy Chung and the natural-history-first model.

Sources

• Nakamura K, Kodera H, Akita T, et al. De novo mutations in GNAO1, encoding a Galphao subunit of heterotrimeric G proteins, cause epileptic encephalopathy. Am J Hum Genet. 2013;93(3):496-505. PMID: 23993195.
• Feng H, Larrivee CL, Demireva EY, et al. Mouse models of GNAO1-associated movement disorder: allele- and sex-specific differences in phenotypes. PLoS One. 2019;14(1):e0211066.
• The Bow Foundation. Foundation history, research grant program, and patient registry. https://gnao1.org
• The Bow Foundation. Bow Foundation announces $540,000 in rare disease research grants. 2024.
• n-Lorem Foundation. Nano-rare Patient Colloquium 2025 recap (references active GNAO1 program). https://www.nlorem.org
• Jennifer Friedman, MD. Rady Children's Hospital and UCSD School of Medicine faculty profile. https://www.rchsd.org/doctors/jennifer-friedman-md/
• Orphan Disease Center, University of Pennsylvania. Bow Foundation awarded grants. https://www.orphandiseasecenter.med.upenn.edu/awarded-grants/category/Bow+Foundation