New York, NY, April 10, 2025 (GLOBE NEWSWIRE) — A seminal study from researchers at the Icahn School of Medicine at Mount Sinai and their collaborators in the United Kingdom, Belgium, Spain, the Netherlands, and Iceland has uncovered a new genetic cause of neurodevelopmental disorders (NDDs). The discovery offers both closure and hope to potentially thousands of families worldwide who have long been searching for answers.
The study, published in the April 10 online issue of Nature Genetics [DOI: 10.1038/s41588-025-02159-5], reveals that mutations in a small, previously overlooked non-coding gene called RNU2-2 are responsible for relatively common NDD. Non-coding genes are genes that don’t produce proteins but may still play critical roles in regulating cell functions.
Building on their landmark discovery of RNU4-2 / ReNU syndrome last year, the research team has identified the new, related disorder caused by mutations in the non-coding gene RNU2-2. RNU4-2 / ReNU syndrome and RNU2-2 syndromes share similarities, but patients with RNU2-2 syndrome tend to be more severely affected by epilepsy.
“Our identification of RNU2-2 mutations as a cause of NDDs is particularly notable because it cements the biological significance of a class of small non-coding genes in NDDs,” says the study’s first author, Daniel Greene, PhD, Assistant Professor of Genetics and Genomic Sciences at the Icahn School of Medicine at Mount Sinai. “These mutations tend to occur spontaneously, rather than being inherited from an affected person’s parents.”
NDDs are disorders that affect the development of the brain and nervous system. They include conditions such as intellectual disability, autism spectrum disorder, and motor disorders. These NDDs, which often have a genetic basis, manifest in early childhood and can lead to lifelong challenges in learning, behavior, and communication. The current findings involve a newly discovered form of NDD.
“We know from years of experience supporting patients and families with rare genetic conditions how receiving a diagnosis like this can be life-changing and the first step on the journey to putting in place the right support and care,” says Sarah Wynn, PhD, Chief Executive Officer of Unique, an organization that provides support, information, and a voice for all those affected by rare chromosome or gene disorders.
Advances in genetic sequencing, including whole-genome sequencing of more than 50,000 individuals by Genomics England, made the development possible. This enabled the researchers to identify the cause of the novel disorder as mutations in RNU2-2, a gene once thought to be inactive. The authors also identified a separate mutation in RNU2-2 that tends to arise in unaffected individuals as they age, which may have implications for age-related conditions.
“We estimate that the prevalence of RNU2-2 disorder is approximately 20 percent that of RNU4-2 / ReNU syndrome, one of the most common monogenic types of NDD. This means there must be thousands of affected families worldwide,” says senior study author Ernest Turro, PhD, Associate Professor of Genetics and Genomic Sciences at the Icahn School of Medicine at Mount Sinai.
“With a genetic diagnosis in hand, families can connect with others in similar situations, share valuable experiences, and gain a better understanding of how to manage the condition. This discovery also makes possible further research to explore the molecular mechanisms underlying the disorder,” says Dr. Turro.
The paper is titled “Mutations in the snRNA gene RNU2-2 cause a severe neurodevelopmental disorder with prominent epilepsy.”
For the full list of authors, as well as details on funding and competing interests, please refer to the Nature Genetics paper: [DOI: 10.1038/s41588-025-02159-5].
About the Icahn School of Medicine at Mount Sinai
The Icahn School of Medicine at Mount Sinai is internationally renowned for its outstanding research, educational, and clinical care programs. It is the sole academic partner for the seven member hospitals* of the Mount Sinai Health System, one of the largest academic health systems in the United States, providing care to New York City’s large and diverse patient population.
The Icahn School of Medicine at Mount Sinai offers highly competitive MD, PhD, MD-PhD, and master’s degree programs, with enrollment of more than 1,200 students. It has the largest graduate medical education program in the country, with more than 2,600 clinical residents and fellows training throughout the Health System. Its Graduate School of Biomedical Sciences offers 13 degree-granting programs, conducts innovative basic and translational research, and trains more than 560 postdoctoral research fellows.
Ranked 11th nationwide in National Institutes of Health (NIH) funding, the Icahn School of Medicine at Mount Sinai is among the 99th percentile in research dollars per investigator according to the Association of American Medical Colleges. More than 4,500 scientists, educators, and clinicians work within and across dozens of academic departments and multidisciplinary institutes with an emphasis on translational research and therapeutics. Through Mount Sinai Innovation Partners (MSIP), the Health System facilitates the real-world application and commercialization of medical breakthroughs made at Mount Sinai.
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About the Mount Sinai Health System
Mount Sinai Health System is one of the largest academic medical systems in the New York metro area, employing 48,000 people across its hospitals and more than 400 outpatient practices, as well as more than 600 research and clinical labs, a school of nursing, and a leading school of medicine and graduate education. Mount Sinai advances health for all people, everywhere, by taking on the most complex health care challenges of our time—discovering and applying new scientific learning and knowledge; developing safer, more effective treatments; educating the next generation of medical leaders and innovators; and supporting local communities by delivering high-quality care to all who need it.
Through the integration of its hospitals, labs, and schools, Mount Sinai offers comprehensive health care solutions from birth through geriatrics, leveraging innovative approaches such as artificial intelligence and informatics while keeping patients’ medical and emotional needs at the center of all treatment. The Health System includes approximately 9,000 primary and specialty care physicians and 11 free-standing joint-venture centers throughout the five boroughs of New York City, Westchester, Long Island, and Florida. Hospitals within the System are consistently ranked by Newsweek’s® “The World’s Best Smart Hospitals, Best in State Hospitals, World Best Hospitals and Best Specialty Hospitals” and by U.S. News & World Report‘s® “Best Hospitals” and “Best Children’s Hospitals.” The Mount Sinai Hospital is on the U.S. News & World Report® “Best Hospitals” Honor Roll for 2024-2025.
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