We were founded on a passionate belief that innovation in gene therapy can bring treatment options to patients with complex neurological diseases—patients who are waiting with unmet needs and often overlooked.

Our Approach

The heart of our work is bringing the patient community's perspective into everything we do. Patients and families affected by rare conditions are experts and their input is critical for helping us understand how these conditions affect everyday life and what matters most to them. These learnings guide how we develop potential treatments and conduct research.

We recognize and honor that it is their contributions and efforts that make scientific advances possible. Our gratitude goes to every family who chooses to join clinical research, and we are committed to supporting them throughout their journey.

What is Rett Syndrome?

Rett syndrome is a rare, X-linked, progressive, genetic neurodevelopmental disorder. It has an estimated worldwide incidence of 1 out of every 10,000 live female births.

The condition is caused by variants in the MECP2 gene that lead to deficiency of the methyl cytosine binding protein 2, an important protein responsible for normal function in the brain and other parts of the nervous system.

Rett syndrome occurs almost exclusively in females, and the incidence in males is currently unknown. Advances in genetic testing and phenotypic identification have revealed that MECP2 variants in males are responsible for a wide spectrum of neurological disorders, including Rett syndrome.

The impact on patients and families is profound. Rett syndrome leads to severe impairments that affect nearly every aspect of patients’ lives. This includes their ability to speak, walk, eat and breathe. Most females are nonverbal, lack motor skills and require 24-hour care for all activities of daily living. Many females with Rett syndrome appear to understand the world around them, leaving many caregivers feeling that their daughters are intellectually and emotionally intact.

Females with Rett syndrome typically have normal development until 6–18 months of age, followed by a progressive deterioration of acquired skills such as gross and fine motor skills, purposeful hand function and communication. They subsequently develop stereotypic hand movements such as handwringing.

Over time, females may develop muscle contractures, rigidity, and debilitating scoliosis, along with periods of recurrent seizures, and burdensome gastrointestinal and breathing abnormalities.

Although there is one approved treatment for Rett syndrome, there is no treatment option that addresses the root cause of disease, and a significant unmet need still exists for new treatment options.

Community Perspectives

We are grateful to patients and families who share their experience and perspectives with us. Hear directly from families affected by Rett syndrome.

Rett Syndrome Resources

Our commitment to patients and families affected by Rett syndrome goes beyond the science; we want to raise awareness and connect them with helpful resources.

International Rett Syndrome Foundation

International Rett Syndrome FoundationThe International Rett Syndrome Foundation's mission is to accelerate full spectrum research to cure Rett syndrome and empower families with information, knowledge, and connectivity.

Rett Syndrome Research Trust

Rett Syndrome Research TrustThe singular goal of the Rett Syndrome Research Trust is to find cures for Rett syndrome as efficiently and quickly as possible.

Reverse Rett

Reverse RettReverse Rett is a UK charity driving treatments and a cure for Rett syndrome into the lives of everyone affected.

Rett UK

Rett UKRett UK is a national charity dedicated to supporting and empowering people with Rett syndrome and their families.

Rett Syndrome Association of Australia

Rett Syndrome Association of AustraliaThe Rett Syndrome Association of Australia Inc. (RSAA) is a not-for-profit organization that is managed by a committee of volunteers, most of whom are parents or grandparents of Rett syndrome children. The Association seeks to enhance the quality of life for people with the syndrome and their families and be of assistance to anyone interested in the disorder.

Rett Syndrome Europe

Rett Syndrome EuropeRett Syndrome Europe is a small, not for profit, voluntary led organization to serve the interests of families across Europe affected by this devastating disorder. The board is comprised of parents of people with Rett syndrome.

 

Rett Syndrome Clinical Program

We are evaluating our investigational gene therapy for Rett syndrome, NGN-401, in a clinical trial called Embolden™.

NGN-401 is delivered by an adeno-associated virus (AAV) to the brain through a one-time surgical procedure. Some viruses, such as AAV, are good at delivering genetic material like NGN-401 to cells in the body. When a virus is used in this way, it does not cause disease.

We have shared findings from our Phase 1/2 clinical trial that have shown multidomain, durable gains with continued developmental milestone/skill acquisition in pediatric participants who received the 1E15 vg dose of NGN-401 as of the data cutoff date of October 30, 2025.

Embolden Clinical Trial Frequently Asked Questions

  • Gene therapy is a medical approach designed to deliver a working copy of a gene to a person’s body to treat a genetic disorder like Rett syndrome.
  • Rett syndrome is caused by variants in a single gene called MECP2. Delivering a working copy of the gene may be able to treat the disease.

  • Embolden is an open-label, baseline-controlled trial evaluating a single dose of NGN-401 gene therapy at the 1E15 vg dose. This is a clinical trial where all participants receive the investigational gene therapy product.

  • The investigational gene therapy is given as a single intracerebroventricular (ICV) administration into the brain.
  • ICV delivery has shown in preclinical studies to have the broadest targeting of brain and nervous system regions that underly the development and progression of Rett syndrome.

  • Individuals may be eligible to join Embolden if they meet the following criteria:
    • Female diagnosed with classic Rett syndrome
    • Has a variant in the MECP2 gene
    • 3 years old or older
    • Is post-regression
    • Has a committed primary caregiver with the time and ability to complete all required study tasks
    • Meets other study requirements

  • Interested families should directly contact a clinical trial site that is currently enrolling.
  • The contact information for all the clinical trial sites is available at clinicaltrials.gov.

Embolden Clinical Trial Downloads

Patient Advocacy & Engagement at Neurogene

Kim Trant - Executive Director, Patient Advocacy & EngagementKimberly Trant, RN, MBA

Executive Director
Patient Advocacy & Engagement

+1 (877) 237-5020
[email protected]

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