1. Specific heterozygous frameshift variants in hnRNPA2B1 cause early-onset oculopharyngeal muscular dystrophy
- Author
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Ambegaonkar G, Evangelista T, Maura Coughlin, O’Donovan Dg, Mark A. Tarnopolsky, Tobias B. Haack, Sarah Ennis, Foley Ar, Shatillo A, Zaharieva It, Lornage X, Sato A, Sandra Donkervoort, Nelson I, Grimmel M, Salviati L, Francesco Muntoni, Bello L, Lauren Brady, James Shorter, Iida A, Böhm J, Maja Steinlin, Ana Töpf, Ichizo Nishino, Péréon Y, Quijano-Roy S, Carsten G. Bönnemann, Ogasawara M, Hu Y, Alice Flynn Ford, Klein A, Kevin J. O'Donovan, Raymond Fl, Kuster A, Marcorelles P, Adnan Y. Manzur, Buchert R, Charlotte M. Fare, Hammans, Romero Nb, Munot P, Bertolin C, Upstill-Goddard R, Mercier S, Stojkovic T, Thomas E. Lloyd, Fleurence E, Lin Guo, Courtney E. French, Phadke R, Laporte J, Taylor Jp, Payam Mohassel, Straub, Elena Pegoraro, Hong Joo Kim, and Foulds N
- Subjects
Genetics ,medicine ,Missense mutation ,Muscular dystrophy ,Amyotrophic lateral sclerosis ,medicine.symptom ,Biology ,medicine.disease ,Myopathy ,Phenotype ,Frameshift mutation ,Frontotemporal dementia ,Oculopharyngeal muscular dystrophy - Abstract
SummaryRNA-binding proteins (RBPs) are essential for post-transcriptional regulation and processing of RNAs. Pathogenic missense variants in RBPs underlie a spectrum of disease phenotypes, including amyotrophic lateral sclerosis, frontotemporal dementia, inclusion body myopathy, distal myopathy, and Paget’s disease of the bone. Here, we present ten independent families with a severe, progressive, early-onset muscular dystrophy, reminiscent of oculopharyngeal muscular dystrophy (OPMD), caused by heterozygous frameshift variants in the prion-like domain of hnRNPA2B1. We found that in contrast with the previously reported missense variants, the frameshift hnRNPA2B1 variants do not promote, but rather decelerate the fibrillization of the protein. Importantly, the frameshift variants harbor altered nuclear-localization sequences and exhibit reduced affinity for the nuclear-import receptor, Karyopherin-β2, which promotes their cytoplasmic accumulation in cells and in animal models that recapitulate the human pathology. Thus, we expand the phenotypes associated with hnRNPA2B1 to include a severe, early-onset disease reminiscent of OPMD, caused by a distinct class of frameshift variants that alter its nucleocytoplasmic transport dynamics.
- Published
- 2021