@article {906, title = {Monogenic variants in dystonia: an exome-wide sequencing study.}, journal = {Lancet Neurol}, volume = {19}, year = {2020}, month = {2020 11}, pages = {908-918}, abstract = {

BACKGROUND: Dystonia is a clinically and genetically heterogeneous condition that occurs in isolation (isolated dystonia), in combination with other movement disorders (combined dystonia), or in the context of multisymptomatic phenotypes (isolated or combined dystonia with other neurological involvement). However, our understanding of its aetiology is still incomplete. We aimed to elucidate the monogenic causes for the major clinical categories of dystonia.

METHODS: For this exome-wide sequencing study, study participants were identified at 33 movement-disorder and neuropaediatric specialty centres in Austria, Czech Republic, France, Germany, Poland, Slovakia, and Switzerland. Each individual with dystonia was diagnosed in accordance with the dystonia consensus definition. Index cases were eligible for this study if they had no previous genetic diagnosis and no indication of an acquired cause of their illness. The second criterion was not applied to a subset of participants with a working clinical diagnosis of dystonic cerebral palsy. Genomic DNA was extracted from blood of participants and whole-exome sequenced. To find causative variants in known disorder-associated genes, all variants were filtered, and unreported variants were classified according to American College of Medical Genetics and Genomics guidelines. All considered variants were reviewed in expert round-table sessions to validate their clinical significance. Variants that survived filtering and interpretation procedures were defined as diagnostic variants. In the cases that went undiagnosed, candidate dystonia-causing genes were prioritised in a stepwise workflow.

FINDINGS: We sequenced the exomes of 764 individuals with dystonia and 346 healthy parents who were recruited between June 1, 2015, and July 31, 2019. We identified causative or probable causative variants in 135 (19\%) of 728 families, involving 78 distinct monogenic disorders. We observed a larger proportion of individuals with diagnostic variants in those with dystonia (either isolated or combined) with coexisting non-movement disorder-related neurological symptoms (100 [45\%] of 222; excepting cases with evidence of perinatal brain injury) than in those with combined (19 [19\%] of 98) or isolated (16 [4\%] of 388) dystonia. Across all categories of dystonia, 104 (65\%) of the 160 detected variants affected genes which are associated with neurodevelopmental disorders. We found diagnostic variants in 11 genes not previously linked to dystonia, and propose a predictive clinical score that could guide the implementation of exome sequencing in routine diagnostics. In cases without perinatal sentinel events, genomic alterations contributed substantively to the diagnosis of dystonic cerebral palsy. In 15 families, we delineated 12 candidate genes. These include IMPDH2, encoding a key purine biosynthetic enzyme, for which robust evidence existed for its involvement in a neurodevelopmental disorder with dystonia. We identified six variants in IMPDH2, collected from four independent cohorts, that were predicted to be deleterious de-novo variants and expected to result in deregulation of purine metabolism.

INTERPRETATION: In this study, we have determined the role of monogenic variants across the range of dystonic disorders, providing guidance for the introduction of personalised care strategies and fostering follow-up pathophysiological explorations.

FUNDING: Else Kr{\"o}ner-Fresenius-Stiftung, Technische Universit{\"a}t M{\"u}nchen, Helmholtz Zentrum M{\"u}nchen, Medizinische Universit{\"a}t Innsbruck, Charles University in Prague, Czech Ministry of Education, the Slovak Grant and Development Agency, the Slovak Research and Grant Agency.

}, keywords = {Adolescent, Child, Child, Preschool, Dystonia, Exome, Female, Genetic Variation, Humans, Infant, Infant, Newborn, Male, Pedigree, Whole Exome Sequencing, Young Adult}, issn = {1474-4465}, doi = {10.1016/S1474-4422(20)30312-4}, author = {Zech, Michael and Jech, Robert and Boesch, Sylvia and {\v S}korv{\'a}nek, Matej and Weber, Sandrina and Wagner, Matias and Zhao, Chen and Jochim, Angela and Necp{\'a}l, J{\'a}n and Dincer, Yasemin and Vill, Katharina and Distelmaier, Felix and Stoklosa, Malgorzata and Krenn, Martin and Grunwald, Stephan and Bock-Bierbaum, Tobias and Fe{\v c}{\'\i}kov{\'a}, Anna and Havr{\'a}nkov{\'a}, Petra and Roth, Jan and P{\v r}{\'\i}hodov{\'a}, Iva and Adamovi{\v c}ov{\'a}, Miriam and Ulmanov{\'a}, Olga and Bechyn{\v e}, Karel and Danhofer, Pavl{\'\i}na and Vesel{\'y}, Branislav and Ha{\v n}, Vladim{\'\i}r and Pavelekova, Petra and Gdovinov{\'a}, Zuzana and Mantel, Tobias and Meindl, Tobias and Sitzberger, Alexandra and Schr{\"o}der, Sebastian and Blaschek, Astrid and Roser, Timo and Bonfert, Michaela V and Haberlandt, Edda and Plecko, Barbara and Leineweber, Birgit and Berweck, Steffen and Herberhold, Thomas and Langguth, Berthold and {\v S}vantnerov{\'a}, Jana and Min{\'a}r, Michal and Ramos-Rivera, Gonzalo Alonso and Wojcik, Monica H and Pajusalu, Sander and {\~O}unap, Katrin and Schatz, Ulrich A and P{\"o}lsler, Laura and Milenkovic, Ivan and Laccone, Franco and Pilshofer, Veronika and Colombo, Roberto and Patzer, Steffi and Iuso, Arcangela and Vera, Julia and Troncoso, Monica and Fang, Fang and Prokisch, Holger and Wilbert, Friederike and Eckenweiler, Matthias and Graf, Elisabeth and Westphal, Dominik S and Riedhammer, Korbinian M and Brunet, Theresa and Alhaddad, Bader and Berutti, Riccardo and Strom, Tim M and Hecht, Martin and Baumann, Matthias and Wolf, Marc and Telegrafi, Aida and Person, Richard E and Zamora, Francisca Millan and Henderson, Lindsay B and Weise, David and Musacchio, Thomas and Volkmann, Jens and Szuto, Anna and Becker, Jessica and Cremer, Kirsten and Sycha, Thomas and Zimprich, Fritz and Kraus, Verena and Makowski, Christine and Gonzalez-Alegre, Pedro and Bardakjian, Tanya M and Ozelius, Laurie J and Vetro, Annalisa and Guerrini, Renzo and Maier, Esther and Borggraefe, Ingo and Kuster, Alice and Wortmann, Saskia B and Hackenberg, Annette and Steinfeld, Robert and Assmann, Birgit and Staufner, Christian and Opladen, Thomas and R{\r u}{\v z}i{\v c}ka, Ev{\v z}en and Cohn, Ronald D and Dyment, David and Chung, Wendy K and Engels, Hartmut and Ceballos-Baumann, Andres and Ploski, Rafal and Daumke, Oliver and Haslinger, Bernhard and Mall, Volker and Oexle, Konrad and Winkelmann, Juliane} } @article {454, title = {P4HA1 mutations cause a unique congenital disorder of connective tissue involving tendon, bone, muscle and the eye.}, journal = {Hum Mol Genet}, volume = {26}, year = {2017}, month = {2017 06 15}, pages = {2207-2217}, abstract = {

Collagen prolyl 4-hydroxylases (C-P4Hs) play a central role in the formation and stabilization of the triple helical domain of collagens. P4HA1 encodes the catalytic α(I) subunit of the main C-P4H isoenzyme (C-P4H-I). We now report human bi-allelic P4HA1 mutations in a family with a congenital-onset disorder of connective tissue, manifesting as early-onset joint hypermobility, joint contractures, muscle weakness and bone dysplasia as well as high myopia, with evidence of clinical improvement of motor function over time in the surviving patient. Similar to P4ha1 null mice, which die prenatally, the muscle tissue from P1 and P2 was found to have reduced collagen IV immunoreactivity at the muscle basement membrane. Patients were compound heterozygous for frameshift and splice site mutations leading to reduced, but not absent, P4HA1 protein level and C-P4H activity in dermal fibroblasts compared to age-matched control samples. Differential scanning calorimetry revealed reduced thermal stability of collagen in patient-derived dermal fibroblasts versus age-matched control samples. Mutations affecting the family of C-P4Hs, and in particular C-P4H-I, should be considered in patients presenting with congenital connective tissue/myopathy overlap disorders with joint hypermobility, contractures, mild skeletal dysplasia and high myopia.

}, keywords = {Animals, Basement Membrane, Bone and Bones, Child, Collagen Type IV, Connective Tissue, Humans, Male, Mice, Mice, Knockout, Muscles, Mutation, Osteochondrodysplasias, Procollagen-Proline Dioxygenase, Prolyl Hydroxylases, Tendons}, issn = {1460-2083}, doi = {10.1093/hmg/ddx110}, author = {Zou, Yaqun and Donkervoort, Sandra and Salo, Antti M and Foley, A Reghan and Barnes, Aileen M and Hu, Ying and Makareeva, Elena and Leach, Meganne E and Mohassel, Payam and Dastgir, Jahannaz and Deardorff, Matthew A and Cohn, Ronald D and DiNonno, Wendy O and Malfait, Fransiska and Lek, Monkol and Leikin, Sergey and Marini, Joan C and Myllyharju, Johanna and B{\"o}nnemann, Carsten G} } @article {334, title = {A Recurrent De Novo Variant in NACC1 Causes a Syndrome Characterized by Infantile Epilepsy, Cataracts, and Profound Developmental Delay.}, journal = {Am J Hum Genet}, volume = {100}, year = {2017}, month = {2017 Feb 02}, pages = {343-351}, abstract = {

Whole-exome sequencing (WES) has increasingly enabled new pathogenic gene variant identification for undiagnosed neurodevelopmental disorders and provided insights into both gene function and disease biology. Here, we describe seven children with a neurodevelopmental disorder characterized by microcephaly, profound developmental delays and/or intellectual disability, cataracts, severe epilepsy including infantile spasms, irritability, failure to thrive, and stereotypic hand movements. Brain imaging in these individuals reveals delay in myelination and cerebral atrophy. We observe an identical recurrent de novo heterozygous c.892C>T (p.Arg298Trp) variant in the nucleus accumbens associated 1 (NACC1) gene in seven affected individuals. One of the seven individuals is mosaic for this variant. NACC1 encodes a transcriptional repressor implicated in gene expression and has not previously been associated with germline disorders. The probability of finding the same missense NACC1 variant by chance in 7 out of 17,228 individuals who~underwent WES for diagnoses of neurodevelopmental phenotypes is extremely small and achieves genome-wide significance (p~= 1.25~{\texttimes} 10). Selective constraint against missense variants in NACC1 makes this excess of an identical missense variant in all seven individuals more remarkable. Our findings are consistent with a germline recurrent mutational hotspot associated with an allele-specific neurodevelopmental phenotype in NACC1.

}, keywords = {Alleles, Amino Acid Sequence, Brain, Cataract, Child, Child, Preschool, Female, Genetic Variation, Genome-Wide Association Study, Humans, Infant, Intellectual Disability, Magnetic Resonance Imaging, Male, Microcephaly, Mutation, Missense, Neoplasm Proteins, Pedigree, Phenotype, Repressor Proteins, Spasms, Infantile}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2016.12.013}, author = {Schoch, Kelly and Meng, Linyan and Szelinger, Szabolcs and Bearden, David R and Stray-Pedersen, Asbjorg and Busk, Oyvind L and Stong, Nicholas and Liston, Eriskay and Cohn, Ronald D and Scaglia, Fernando and Rosenfeld, Jill A and Tarpinian, Jennifer and Skraban, Cara M and Deardorff, Matthew A and Friedman, Jeremy N and Akdemir, Zeynep Coban and Walley, Nicole and Mikati, Mohamad A and Kranz, Peter G and Jasien, Joan and McConkie-Rosell, Allyn and McDonald, Marie and Wechsler, Stephanie Burns and Freemark, Michael and Kansagra, Sujay and Freedman, Sharon and Bali, Deeksha and Millan, Francisca and Bale, Sherri and Nelson, Stanley F and Lee, Hane and Dorrani, Naghmeh and Goldstein, David B and Xiao, Rui and Yang, Yaping and Posey, Jennifer E and Martinez-Agosto, Julian A and Lupski, James R and Wangler, Michael F and Shashi, Vandana} }