@article {911, title = {Sequential targeted exome sequencing of 1001 patients affected by unexplained limb-girdle weakness.}, journal = {Genet Med}, volume = {22}, year = {2020}, month = {2020 09}, pages = {1478-1488}, abstract = {

PURPOSE: Several hundred genetic muscle diseases have been described, all of which are rare. Their clinical and genetic heterogeneity means that a genetic diagnosis is challenging. We established an international consortium, MYO-SEQ, to aid the work-ups of muscle disease patients and to better understand disease etiology.

METHODS: Exome sequencing was applied to 1001 undiagnosed patients recruited from more than 40 neuromuscular disease referral centers; standardized phenotypic information was collected for each patient. Exomes were examined for variants in 429 genes associated with muscle conditions.

RESULTS: We identified suspected pathogenic variants in 52\% of patients across 87 genes. We detected 401 novel variants, 116 of which were recurrent. Variants in CAPN3, DYSF, ANO5, DMD, RYR1, TTN, COL6A2, and SGCA collectively accounted for over half of the solved cases; while variants in newer disease genes, such as BVES and POGLUT1, were also found. The remaining well-characterized unsolved patients (48\%) need further investigation.

CONCLUSION: Using our unique infrastructure, we developed a pathway to expedite muscle disease diagnoses. Our data suggest that exome sequencing should be used for pathogenic variant detection in patients with suspected genetic muscle diseases, focusing first on the most common disease genes described here, and subsequently in rarer and newly characterized disease genes.

}, keywords = {Anoctamins, Exome, Glucosyltransferases, Humans, Muscular Dystrophies, Limb-Girdle, Whole Exome Sequencing}, issn = {1530-0366}, doi = {10.1038/s41436-020-0840-3}, author = {Topf, Ana and Johnson, Katherine and Bates, Adam and Phillips, Lauren and Chao, Katherine R and England, Eleina M and Laricchia, Kristen M and Mullen, Thomas and Valkanas, Elise and Xu, Liwen and Bertoli, Marta and Blain, Alison and Casas{\'u}s, Ana B and Duff, Jennifer and Mroczek, Magdalena and Specht, Sabine and Lek, Monkol and Ensini, Monica and MacArthur, Daniel G and Straub, Volker} } @article {836, title = {A structural variation reference for medical and population genetics.}, journal = {Nature}, volume = {581}, year = {2020}, month = {2020 05}, pages = {444-451}, abstract = {

Structural variants (SVs) rearrange large segments of DNA and can have profound consequences in evolution and human disease. As national biobanks, disease-association studies, and clinical genetic testing have grown increasingly reliant on genome sequencing, population references such as the Genome Aggregation Database (gnomAD) have become integral in the interpretation of single-nucleotide variants (SNVs). However, there are no reference maps of SVs from high-coverage genome sequencing comparable to those for SNVs. Here we present a reference of sequence-resolved SVs constructed from 14,891 genomes across diverse global populations (54\% non-European) in gnomAD. We discovered a rich and complex landscape of 433,371 SVs, from which we estimate that SVs are responsible for 25-29\% of all rare protein-truncating events per genome. We found strong correlations between natural selection against damaging SNVs and rare SVs that disrupt or duplicate protein-coding sequence, which suggests that genes that are highly intolerant to loss-of-function are also sensitive to increased dosage. We also uncovered modest selection against noncoding SVs in cis-regulatory elements, although selection against protein-truncating SVs was stronger than all noncoding effects. Finally, we identified very large (over one megabase), rare SVs in 3.9\% of samples, and estimate that 0.13\% of individuals may carry an SV that meets the existing criteria for clinically important incidental findings. This SV resource is freely distributed via the gnomAD browser and will have broad utility in population genetics, disease-association studies, and diagnostic screening.

}, keywords = {Continental Population Groups, Disease, Female, Genetic Testing, Genetic Variation, Genetics, Medical, Genetics, Population, Genome, Human, Genotyping Techniques, Humans, Male, Middle Aged, Mutation, Polymorphism, Single Nucleotide, Reference Standards, Selection, Genetic, Whole Genome Sequencing}, issn = {1476-4687}, doi = {10.1038/s41586-020-2287-8}, author = {Collins, Ryan L and Brand, Harrison and Karczewski, Konrad J and Zhao, Xuefang and Alf{\"o}ldi, Jessica and Francioli, Laurent C and Khera, Amit V and Lowther, Chelsea and Gauthier, Laura D and Wang, Harold and Watts, Nicholas A and Solomonson, Matthew and O{\textquoteright}Donnell-Luria, Anne and Baumann, Alexander and Munshi, Ruchi and Walker, Mark and Whelan, Christopher W and Huang, Yongqing and Brookings, Ted and Sharpe, Ted and Stone, Matthew R and Valkanas, Elise and Fu, Jack and Tiao, Grace and Laricchia, Kristen M and Ruano-Rubio, Valentin and Stevens, Christine and Gupta, Namrata and Cusick, Caroline and Margolin, Lauren and Taylor, Kent D and Lin, Henry J and Rich, Stephen S and Post, Wendy S and Chen, Yii-Der Ida and Rotter, Jerome I and Nusbaum, Chad and Philippakis, Anthony and Lander, Eric and Gabriel, Stacey and Neale, Benjamin M and Kathiresan, Sekar and Daly, Mark J and Banks, Eric and MacArthur, Daniel G and Talkowski, Michael E} } @article {586, title = {Contribution of noncoding pathogenic variants to RPGRIP1-mediated inherited retinal degeneration.}, journal = {Genet Med}, volume = {21}, year = {2019}, month = {2019 03}, pages = {694-704}, abstract = {

PURPOSE: With the advent of gene therapies for inherited retinal degenerations (IRDs), genetic diagnostics will have an increasing role in clinical decision-making. Yet the genetic cause of disease cannot be identified using exon-based sequencing for a significant portion of patients. We hypothesized that noncoding pathogenic variants contribute significantly to the genetic causality of IRDs and evaluated patients with single coding pathogenic variants in RPGRIP1 to test this hypothesis.

METHODS: IRD families underwent targeted panel sequencing. Unsolved cases were explored by exome and genome sequencing looking for additional pathogenic variants. Candidate pathogenic variants were then validated by Sanger sequencing, quantitative polymerase chain reaction, and in vitro splicing assays in two cell lines analyzed through amplicon sequencing.

RESULTS: Among 1722 families, 3 had biallelic loss-of-function pathogenic variants in RPGRIP1 while 7 had a single disruptive coding pathogenic variants. Exome and genome sequencing revealed potential noncoding pathogenic variants in these 7 families. In 6, the noncoding pathogenic variants were shown to lead to loss of function in vitro.

CONCLUSION: Noncoding pathogenic variants were identified in 6 of 7 families with single coding pathogenic variants in RPGRIP1. The results suggest that noncoding pathogenic variants contribute significantly to the genetic causality of IRDs and RPGRIP1-mediated IRDs are more common than previously thought.

}, keywords = {Adult, Chromosome Mapping, DNA Mutational Analysis, DNA, Intergenic, Female, HEK293 Cells, Humans, Male, Mutation, Pedigree, Proteins, Retinal Degeneration, Whole Exome Sequencing, Whole Genome Sequencing}, issn = {1530-0366}, doi = {10.1038/s41436-018-0104-7}, author = {Jamshidi, Farzad and Place, Emily M and Mehrotra, Sudeep and Navarro-Gomez, Daniel and Maher, Mathew and Branham, Kari E and Valkanas, Elise and Cherry, Timothy J and Lek, Monkol and Macarthur, Daniel and Pierce, Eric A and Bujakowska, Kinga M} } @article {487, title = {Detection of variants in dystroglycanopathy-associated genes through the application of targeted whole-exome sequencing analysis to a large cohort of patients with unexplained limb-girdle muscle weakness.}, journal = {Skelet Muscle}, volume = {8}, year = {2018}, month = {2018 07 30}, pages = {23}, abstract = {

BACKGROUND: Dystroglycanopathies are a clinically and genetically heterogeneous group of disorders that are typically characterised by limb-girdle muscle weakness. Mutations in 18 different genes have been associated with dystroglycanopathies, the encoded proteins of which typically modulate the binding of α-dystroglycan to extracellular matrix ligands by altering its glycosylation. This results in a disruption of the structural integrity of the myocyte, ultimately leading to muscle degeneration.

METHODS: Deep phenotypic information was gathered using the PhenoTips online software for 1001 patients with unexplained limb-girdle muscle weakness from 43 different centres across 21 European and Middle Eastern countries. Whole-exome sequencing with at least 250~ng DNA was completed using an Illumina exome capture and a 38~Mb baited target. Genes known to be associated with dystroglycanopathies were analysed for disease-causing variants.

RESULTS: Suspected pathogenic variants were detected in DPM3, ISPD, POMT1 and FKTN in one patient each, in POMK in two patients, in GMPPB in three patients, in FKRP in eight patients and in POMT2 in ten patients. This indicated a frequency of 2.7\% for the disease group within the cohort of 1001 patients with unexplained limb-girdle muscle weakness. The phenotypes of the 27 patients were highly variable, yet with a fundamental presentation of proximal muscle weakness and elevated serum creatine kinase.

CONCLUSIONS: Overall, we have identified 27 patients with suspected pathogenic variants in dystroglycanopathy-associated genes. We present evidence for the genetic and phenotypic diversity of the dystroglycanopathies as a disease group, while also highlighting the advantage of incorporating next-generation sequencing into the diagnostic pathway of rare diseases.

}, keywords = {Adolescent, Adult, Aged, Aged, 80 and over, Child, Child, Preschool, Dystroglycans, Female, Genetic Predisposition to Disease, Genetic Variation, Glycosylation, Heterozygote, Homozygote, Humans, Male, Middle Aged, Muscle Proteins, Muscular Dystrophies, Limb-Girdle, Mutation, Phenotype, Whole Exome Sequencing, Young Adult}, issn = {2044-5040}, doi = {10.1186/s13395-018-0170-1}, author = {Johnson, Katherine and Bertoli, Marta and Phillips, Lauren and Topf, Ana and Van den Bergh, Peter and Vissing, John and Witting, Nanna and Nafissi, Shahriar and Jamal-Omidi, Shirin and {\L}usakowska, Anna and Kostera-Pruszczyk, Anna and Potulska-Chromik, Anna and Deconinck, Nicolas and Wallgren-Pettersson, Carina and Strang-Karlsson, Sonja and Colomer, Jaume and Claeys, Kristl G and De Ridder, Willem and Baets, Jonathan and von der Hagen, Maja and Fern{\'a}ndez-Torr{\'o}n, Roberto and Zulaica Ijurco, Miren and Espinal Valencia, Juan Bautista and Hahn, Andreas and Durmus, Hacer and Willis, Tracey and Xu, Liwen and Valkanas, Elise and Mullen, Thomas E and Lek, Monkol and MacArthur, Daniel G and Straub, Volker} } @article {511, title = {matchbox: An open-source tool for patient matching via the Matchmaker Exchange.}, journal = {Hum Mutat}, volume = {39}, year = {2018}, month = {2018 Dec}, pages = {1827-1834}, abstract = {

Rare disease investigators constantly face challenges in identifying additional cases to build evidence for gene-disease causality. The Matchmaker Exchange (MME) addresses this limitation by providing a mechanism for matching patients across genomic centers via a federated network. The MME has revolutionized searching for additional cases by making it possible to query across institutional boundaries, so that what was once a laborious and manual process of contacting researchers is now automated and computable. However, while the MME network is beginning to scale, the growth of additional nodes is limited by the lack of easy-to-use solutions that can be implemented by any rare disease database owner, even one without significant software engineering resources. Here, we describe matchbox, which is an open-source, platform-independent, portable bridge between any given rare disease genomic center and the MME network, which has already led to novel gene discoveries. We also describe how matchbox greatly reduces the barrier to participation by overcoming challenges for new databases to join the MME.

}, issn = {1098-1004}, doi = {10.1002/humu.23655}, author = {Arachchi, Harindra and Wojcik, Monica H and Weisburd, Benjamin and Jacobsen, Julius O B and Valkanas, Elise and Baxter, Samantha and Byrne, Alicia B and O{\textquoteright}Donnell-Luria, Anne H and Haendel, Melissa and Smedley, Damian and MacArthur, Daniel G and Philippakis, Anthony A and Rehm, Heidi L} } @article {17, title = {The sensitivity of exome sequencing in identifying pathogenic mutations for LGMD in the United States.}, journal = {J Hum Genet}, volume = {62}, year = {2017}, month = {2017 Feb}, pages = {243-252}, abstract = {

The current study characterizes a cohort of limb-girdle muscular dystrophy (LGMD) in the United States using whole-exome sequencing. Fifty-five families affected by LGMD were recruited using an institutionally approved protocol. Exome sequencing was performed on probands and selected parental samples. Pathogenic mutations and cosegregation patterns were confirmed by Sanger sequencing. Twenty-two families (40\%) had novel and previously reported pathogenic mutations, primarily in LGMD genes, and also in genes for Duchenne muscular dystrophy, facioscapulohumeral muscular dystrophy, congenital myopathy, myofibrillar myopathy, inclusion body myopathy and Pompe disease. One family was diagnosed via clinical testing. Dominant mutations were identified in COL6A1, COL6A3, FLNC, LMNA, RYR1, SMCHD1 and VCP, recessive mutations in ANO5, CAPN3, GAA, LAMA2, SGCA and SGCG, and X-linked mutations in DMD. A previously reported variant in DMD was confirmed to be benign. Exome sequencing is a powerful diagnostic tool for LGMD. Despite careful phenotypic screening, pathogenic mutations were found in other muscle disease genes, largely accounting for the increased sensitivity of exome sequencing. Our experience suggests that broad sequencing panels are useful for these analyses because of the phenotypic overlap of many neuromuscular conditions. The confirmation of a benign DMD variant illustrates the potential of exome sequencing to help determine pathogenicity.

}, keywords = {Base Sequence, Distal Myopathies, Exome, Female, Genetic Testing, Glycogen Storage Disease Type II, Humans, Male, Muscular Dystrophies, Limb-Girdle, Muscular Dystrophy, Duchenne, Muscular Dystrophy, Facioscapulohumeral, Mutation, Myopathies, Structural, Congenital, Sequence Analysis, DNA, United States}, issn = {1435-232X}, doi = {10.1038/jhg.2016.116}, author = {Reddy, Hemakumar M and Cho, Kyung-Ah and Lek, Monkol and Estrella, Elicia and Valkanas, Elise and Jones, Michael D and Mitsuhashi, Satomi and Darras, Basil T and Amato, Anthony A and Lidov, Hart Gw and Brownstein, Catherine A and Margulies, David M and Yu, Timothy W and Salih, Mustafa A and Kunkel, Louis M and MacArthur, Daniel G and Kang, Peter B} }