The results of a large-scale genetic study published in the new issue of Nature Medicine suggest that a rare mutation in the RNU4-2 gene may be a contributing factor to more clinical diagnoses of intellectual disabilities compared to any other known non gender related genes. The new discovery is expected to promote the diagnosis and treatment of specific neurodevelopmental diseases. Intellectual disability is a neurodevelopmental disorder characterized by impaired intellectual function and social and practical skills. It is known that 1427 genes are associated with intellectual disabilities, of which all except 9 are protein coding genes. This is partly because the largest genetic research on intellectual disabilities uses whole exome sequencing, which often overlooks non protein coding genes. The research team conducted a genetic association analysis using whole genome sequencing data from 77539 participants in the 100000 Genome Project. They discovered a rare new mutation in the non protein coding gene RNU4-2 that is strongly correlated with the possibility of intellectual disability - the RNU4-2 gene can encode a splicing component. Scissors are molecular machines that can remove introns (non coding regions) from precursor mRNA and connect the remaining exons (coding regions) to form mature mRNA. These associations were further validated in three independent large-scale gene databases, with a total of 73 affected cases found in all four databases. The research team emphasizes that the specific mechanisms behind these mutations are still unclear and need to be further explored in future research. However, these results present a potential genetic etiology for many previously unexplained clinical diagnoses of neurodevelopmental diseases. (Lai Xin She)