posted on 2024-08-28, 12:06authored byYuyang Chen, Ruebena Dawes, Hyung Chul Kim, Alicia Ljungdahl, Sarah L Stenton, Susan Walker, Jenny Lord, Gabrielle Lemire, Alexandra C Martin-Geary, Vijay S Ganesh, Jialan Ma, Jamie M Ellingford, Erwan Delage, Elston N D'Souza, Shan Dong, David R Adams, Kirsten Allan, Madhura Bakshi, Erin E Baldwin, Seth I Berger, Jonathan A Bernstein, Ishita Bhatnagar, Ed Blair, Natasha J Brown, Lindsay C Burrage, Kimberly Chapman, David J Coman, Alison G Compton, Chloe A Cunningham, Precilla D'Souza, Petr Danecek, Emmanuèle C Délot, Kerith-Rae Dias, Ellen R Elias, Frances Elmslie, Care-Anne Evans, Lisa Ewans, Kimberly Ezell, Jamie L Fraser, Lyndon Gallacher, Casie A Genetti, Anne Goriely, Christina L Grant, Tobias Haack, Jenny E Higgs, Anjali G Hinch, Matthew E Hurles, Alma Kuechler, Katherine L Lachlan, Seema R Lalani, François Lecoquierre, Elsa Leitão, Anna Le Fevre, Richard J Leventer, Jan E Liebelt, Sarah Lindsay, Paul J Lockhart, Alan S Ma, Ellen F Macnamara, Sahar Mansour, Taylor M Maurer, Hector R Mendez, Kay Metcalfe, Stephen B Montgomery, Mariya Moosajee, Marie-Cécile Nassogne, Serena Neumann, Michael O'Donoghue, Melanie O'Leary, Elizabeth E Palmer, Nikhil Pattani, John Phillips, Georgia Pitsava, Ryan Pysar, Heidi L Rehm, Chloe M Reuter, Nicole Revencu, Angelika Riess, Rocio Rius, Lance Rodan, Tony Roscioli, Jill A Rosenfeld, Rani Sachdev, Charles J Shaw-Smith, Cas Simons, Sanjay M Sisodiya, Penny Snell, Laura St Clair, Zornitza Stark, Helen S Stewart, Tiong Yang Tan, Natalie B Tan, Suzanna EL Temple, David R Thorburn, Cynthia J Tifft, Eloise Uebergang, Grace E VanNoy, Pradeep Vasudevan, Eric Vilain, David H Viskochil, Laura Wedd, Matthew T Wheeler, Susan M White, Monica Wojcik, Lynne A Wolfe, Zoe Wolfenson, Caroline F Wright, Changrui Xiao, David Zocche, John L Rubenstein, Eirene Markenscoff-Papadimitriou, Sebastian M Fica, Diana Baralle, Christel Depienne, Daniel G MacArthur, Joanna MM Howson, Stephan J Sanders, Anne O'Donnell-Luria, Nicola Whiffin
Around 60% of individuals with neurodevelopmental disorders (NDD) remain undiagnosed after comprehensive genetic testing, primarily of protein-coding genes1. Large genome-sequenced cohorts are improving our ability to discover new diagnoses in the non-coding genome. Here, we identify the non-coding RNA RNU4-2 as a syndromic NDD gene. RNU4-2 encodes the U4 small nuclear RNA (snRNA), which is a critical component of the U4/U6.U5 tri-snRNP complex of the major spliceosome2. We identify an 18 bp region of RNU4-2 mapping to two structural elements in the U4/U6 snRNA duplex (the T-loop and Stem III) that is severely depleted of variation in the general population, but in which we identify heterozygous variants in 115 individuals with NDD. Most individuals (77.4%) have the same highly recurrent single base insertion (n.64_65insT). In 54 individuals where it could be determined, the de novo variants were all on the maternal allele. We demonstrate that RNU4-2 is highly expressed in the developing human brain, in contrast to RNU4-1 and other U4 homologs. Using RNA-sequencing, we show how 5' splice site usage is systematically disrupted in individuals with RNU4-2 variants, consistent with the known role of this region during spliceosome activation. Finally, we estimate that variants in this 18 bp region explain 0.4% of individuals with NDD. This work underscores the importance of non-coding genes in rare disorders and will provide a diagnosis to thousands of individuals with NDD worldwide.