@article {655, title = {A recurrent COL6A1 pseudoexon insertion causes muscular dystrophy and is effectively targeted by splice-correction therapies.}, journal = {JCI Insight}, volume = {4}, year = {2019}, month = {2019 Mar 21}, abstract = {

The clinical application of advanced next-generation sequencing technologies is increasingly uncovering novel classes of mutations that may serve as potential targets for precision medicine therapeutics. Here, we show that a deep intronic splice defect in the COL6A1 gene, originally discovered by applying muscle RNA sequencing in patients with clinical findings of collagen VI-related dystrophy (COL6-RD), inserts an in-frame pseudoexon into COL6A1 mRNA, encodes a mutant collagen α1(VI) protein that exerts a dominant-negative effect on collagen VI matrix assembly, and provides a unique opportunity for splice-correction approaches aimed at restoring normal gene expression. Using splice-modulating antisense oligomers, we efficiently skipped the pseudoexon in patient-derived fibroblast cultures and restored a wild-type matrix. Similarly, we used CRISPR/Cas9 to precisely delete an intronic sequence containing the pseudoexon and efficiently abolish its inclusion while preserving wild-type splicing. Considering that this splice defect is emerging as one of the single most frequent mutations in COL6-RD, the design of specific and effective splice-correction therapies offers a promising path for clinical translation.

}, issn = {2379-3708}, doi = {10.1172/jci.insight.124403}, author = {Bolduc, Veronique and Foley, A Reghan and Solomon-Degefa, Herimela and Sarathy, Apurva and Donkervoort, Sandra and Hu, Ying and Chen, Grace S and Sizov, Katherine and Nalls, Matthew and Zhou, Haiyan and Aguti, Sara and Cummings, Beryl B and Lek, Monkol and Tukiainen, Taru and Marshall, Jamie L and Regev, Oded and Marek-Yagel, Dina and Sarkozy, Anna and Butterfield, Russell J and Jou, Cristina and Jimenez-Mallebrera, Cecilia and Li, Yan and Gartioux, Corine and Mamchaoui, Kamel and Allamand, Val{\'e}rie and Gualandi, Francesca and Ferlini, Alessandra and Hanssen, Eric and Wilton, Steve D and Lamand{\'e}, Shireen R and MacArthur, Daniel G and Wagener, Raimund and Muntoni, Francesco and B{\"o}nnemann, Carsten G} } @article {364, title = {Improving genetic diagnosis in Mendelian disease with transcriptome sequencing.}, journal = {Sci Transl Med}, volume = {9}, year = {2017}, month = {2017 04 19}, abstract = {

Exome and whole-genome sequencing are becoming increasingly routine approaches in Mendelian disease diagnosis. Despite their success, the current diagnostic rate for genomic analyses across a variety of rare diseases is approximately 25 to 50\%. We explore the utility of transcriptome sequencing [RNA sequencing (RNA-seq)] as a complementary diagnostic tool in a cohort of 50 patients with genetically undiagnosed rare muscle disorders. We describe an integrated approach to analyze patient muscle RNA-seq, leveraging an analysis framework focused on the detection of transcript-level changes that are unique to the patient compared to more than 180 control skeletal muscle samples. We demonstrate the power of RNA-seq to validate candidate splice-disrupting mutations and to identify splice-altering variants in both exonic and deep intronic regions, yielding an overall diagnosis rate of 35\%. We also report the discovery of a highly recurrent de novo intronic mutation in that results in a dominantly acting splice-gain event, disrupting the critical glycine repeat motif of the triple helical domain. We identify this pathogenic variant in a total of 27 genetically unsolved patients in an external collagen VI-like dystrophy cohort, thus explaining approximately 25\% of patients clinically suggestive of having collagen VI dystrophy in whom prior genetic analysis is negative. Overall, this study represents a large systematic application of transcriptome sequencing to rare disease diagnosis and highlights its utility for the detection and interpretation of variants missed by current standard diagnostic approaches.

}, keywords = {Collagen Type VI, High-Throughput Nucleotide Sequencing, Humans, Muscular Diseases, Mutation, Transcriptome}, issn = {1946-6242}, doi = {10.1126/scitranslmed.aal5209}, author = {Cummings, Beryl B and Marshall, Jamie L and Tukiainen, Taru and Lek, Monkol and Donkervoort, Sandra and Foley, A Reghan and Bolduc, Veronique and Waddell, Leigh B and Sandaradura, Sarah A and O{\textquoteright}Grady, Gina L and Estrella, Elicia and Reddy, Hemakumar M and Zhao, Fengmei and Weisburd, Ben and Karczewski, Konrad J and O{\textquoteright}Donnell-Luria, Anne H and Birnbaum, Daniel and Sarkozy, Anna and Hu, Ying and Gonorazky, Hernan and Claeys, Kristl and Joshi, Himanshu and Bournazos, Adam and Oates, Emily C and Ghaoui, Roula and Davis, Mark R and Laing, Nigel G and Topf, Ana and Kang, Peter B and Beggs, Alan H and North, Kathryn N and Straub, Volker and Dowling, James J and Muntoni, Francesco and Clarke, Nigel F and Cooper, Sandra T and B{\"o}nnemann, Carsten G and MacArthur, Daniel G} } @article {455, title = {Variants in the Oxidoreductase PYROXD1 Cause Early-Onset Myopathy with Internalized Nuclei and Myofibrillar Disorganization.}, journal = {Am J Hum Genet}, volume = {99}, year = {2016}, month = {2016 Nov 03}, pages = {1086-1105}, abstract = {

This study establishes PYROXD1 variants as a cause of early-onset myopathy and uses biospecimens and cell lines, yeast, and zebrafish models to elucidate the fundamental role of PYROXD1 in skeletal muscle. Exome sequencing identified recessive variants in PYROXD1 in nine probands from five families. Affected individuals presented in infancy or childhood with slowly progressive proximal and distal weakness, facial weakness, nasal speech, swallowing difficulties, and normal to moderately elevated creatine kinase. Distinctive histopathology showed abundant internalized nuclei, myofibrillar disorganization, desmin-positive inclusions, and thickened Z-bands. PYROXD1 is a nuclear-cytoplasmic pyridine nucleotide-disulphide reductase (PNDR). PNDRs are flavoproteins (FAD-binding) and catalyze pyridine-nucleotide-dependent (NAD/NADH) reduction of thiol residues in other proteins. Complementation experiments in yeast lacking glutathione reductase glr1 show that human PYROXD1 has reductase activity that is strongly impaired by the disease-associated missense mutations. Immunolocalization studies in human muscle and zebrafish myofibers demonstrate that PYROXD1 localizes to the nucleus and to striated sarcomeric compartments. Zebrafish with ryroxD1 knock-down recapitulate features of PYROXD1 myopathy with sarcomeric disorganization, myofibrillar aggregates, and marked swimming defect. We characterize variants in the oxidoreductase PYROXD1 as a cause of early-onset myopathy with distinctive histopathology and introduce altered redox regulation as a primary cause of congenital muscle disease.

}, keywords = {Amino Acid Sequence, Animals, Cell Nucleus, Cercopithecus aethiops, Cohort Studies, COS Cells, Creatine Kinase, Cytoplasm, Distal Myopathies, ELAV-Like Protein 4, Female, Flavoproteins, Gene Deletion, Genetic Variation, Genome-Wide Association Study, Glutathione Reductase, HEK293 Cells, Humans, Male, Muscle, Skeletal, Mutation, Missense, Myopathies, Structural, Congenital, Oxidoreductases, Pedigree, Protein Conformation, Saccharomyces cerevisiae Proteins, Zebrafish}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2016.09.005}, author = {O{\textquoteright}Grady, Gina L and Best, Heather A and Sztal, Tamar E and Schartner, Vanessa and Sanjuan-Vazquez, Myriam and Donkervoort, Sandra and Abath Neto, Osorio and Sutton, Roger Bryan and Ilkovski, Biljana and Romero, Norma Beatriz and Stojkovic, Tanya and Dastgir, Jahannaz and Waddell, Leigh B and Boland, Anne and Hu, Ying and Williams, Caitlin and Ruparelia, Avnika A and Maisonobe, Thierry and Peduto, Anthony J and Reddel, Stephen W and Lek, Monkol and Tukiainen, Taru and Cummings, Beryl B and Joshi, Himanshu and Nectoux, Juliette and Brammah, Susan and Deleuze, Jean-Fran{\c c}ois and Ing, Viola Oorschot and Ramm, Georg and Ardicli, Didem and Nowak, Kristen J and Talim, Beril and Topaloglu, Haluk and Laing, Nigel G and North, Kathryn N and MacArthur, Daniel G and Friant, Sylvie and Clarke, Nigel F and Bryson-Richardson, Robert J and B{\"o}nnemann, Carsten G and Laporte, Jocelyn and Cooper, Sandra T} }