Mutations in RNU2-2 Gene Identified as Cause of Neurodevelopmental Disorders

A study from the Icahn School of Medicine at Mount Sinai and collaborators has identified mutations in the non-coding gene RNU2-2 as a cause of neurodevelopmental disorders (NDDs). Published in *Nature Genetics*, the research builds on the prior discovery of RNU4-2 / ReNU syndrome. According to Daniel Greene, PhD, Assistant Professor of Genetics and Genomic Sciences at the Icahn School of Medicine at Mount Sinai, this discovery "cements the biological significance of a class of small non-coding genes in NDDs." He also noted that "these mutations tend to occur spontaneously, rather than being inherited from an affected person's parents." NDDs affect brain and nervous system development, leading to challenges in learning, behavior, and communication. The study identified that RNU2-2 syndrome shares similarities with RNU4-2 / ReNU syndrome, but patients with RNU2-2 syndrome tend to be more severely affected by epilepsy. Sarah Wynn, PhD, Chief Executive Officer of Unique, stated that receiving such a diagnosis can be "life-changing" for patients and families, enabling them to access appropriate support and care. Advances in genetic sequencing, including whole-genome sequencing of over 50,000 individuals by Genomics England, facilitated the identification of RNU2-2 mutations as the cause. 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. Ernest Turro, PhD, Associate Professor of Genetics and Genomic Sciences at the Icahn School of Medicine at Mount Sinai, estimates that "the prevalence of RNU2-2 disorder is approximately 20 percent that of RNU4-2 / ReNU syndrome... This means there must be thousands of affected families worldwide." Dr. Turro added that a genetic diagnosis allows families to connect, share experiences, and better understand how to manage the condition, and it also enables further research into the disorder's molecular mechanisms.