DYNC2H1 hypomorphic or retina-predominant variants cause nonsyndromic retinal degeneration
Anjali Vig, James A. Poulter, Daniele Ottaviani, Erika Tavares, Katerina Toropova, Anna M. Tracewska, Antonio Mollica, Jasmine Kang, Oshini Kehelwathugoda, Tara Paton, Jason T. Maynes, Gabrielle Wheway, Gavin Arno, John C. Ambrose, Prabhu Arumugam, Emma L. Baple, Marta Bleda, F. Boardman-Pretty, J. M. Boissiere, C. R. Boustred, Helen Brittain, Mark J. Caulfield, G. C. Chan, Candice Craig, Louise C. Daugherty, Anna de Burca, A. Devereau, Greg Elgar, Rebecca E. Foulger, Tom Fowler, Pedro Furió‐Tarí, J.M. Hackett, Dina Halai, Angela Hamblin, Shirley Henderson, John E. Holman, Tim Hubbard, Kristina Ibáñez, R. Jackson, J. Louise Jones, Dalia Kasperavičiūtė, Melis Kayikci, L. Lahnstein, Kim Lawson, S. E. A. Leigh, I. U. S. Leong, Fabrice Lopez, F. Maleady-Crowe, Joanne Mason, Ellen M. McDonagh, Loukas Moutsianas, Michael Mueller, Nirupa Murugaesu, Anna C. Need, Christopher A. Odhams, Christine Patch, D. Perez-Gil, Dimitris Polychronopoulos, J. Pullinger, T. Rahim, Augusto Rendon, Pablo Riesgo-Ferreiro, T. Rogers, Mina Ryten, K. Savage, K. Sawant, Richard H. Scott, Afshan Siddiq, A. Sieghart, D. Smedley, Katherine R. Smith, Alona Sosinsky, W. Spooner, Hallam Stevens, Alexander Stuckey, Rosy Sultana, Ellen Thomas, Simon R. Thompson, Carolyn Tregidgo, Arianna Tucci, Elizabeth T. Walsh, Scott Watters, M. J. Welland, Eric O. Williams, Katarzyna Witkowska, S. M. Wood, Magdalena Zarowiecki, Kamron N. Khan, Martin McKibbin, Carmel Toomes, Manir Ali, Matteo Di Scipio, Shuning Li, Jamie M. Ellingford, Graeme C. Black, Andrew R. Webster, Małgorzata Rydzanicz, Piotr Stawiński, Rafał Płoski, Ajoy Vincent
Abstract
PURPOSE: Determining the role of DYNC2H1 variants in nonsyndromic inherited retinal disease (IRD). METHODS: Genome and exome sequencing were performed for five unrelated cases of IRD with no identified variant. In vitro assays were developed to validate the variants identified (fibroblast assay, induced pluripotent stem cell [iPSC] derived retinal organoids, and a dynein motility assay). RESULTS: Four novel DYNC2H1 variants (V1, g.103327020_103327021dup; V2, g.103055779A>T; V3, g.103112272C>G; V4, g.103070104A>C) and one previously reported variant (V5, g.103339363T>G) were identified. In proband 1 (V1/V2), V1 was predicted to introduce a premature termination codon (PTC), whereas V2 disrupted the exon 41 splice donor site causing incomplete skipping of exon 41. V1 and V2 impaired dynein-2 motility in vitro and perturbed IFT88 distribution within cilia. V3, homozygous in probands 2-4, is predicted to cause a PTC in a retina-predominant transcript. Analysis of retinal organoids showed that this new transcript expression increased with organoid differentiation. V4, a novel missense variant, was in trans with V5, previously associated with Jeune asphyxiating thoracic dystrophy (JATD). CONCLUSION: The DYNC2H1 variants discussed herein were either hypomorphic or affecting a retina-predominant transcript and caused nonsyndromic IRD. Dynein variants, specifically DYNC2H1 variants are reported as a cause of non syndromic IRD.