@article {923, title = {Alternative genomic diagnoses for individuals with a clinical diagnosis of Dubowitz syndrome.}, journal = {Am J Med Genet A}, volume = {185}, year = {2021}, month = {2021 01}, pages = {119-133}, abstract = {

Dubowitz syndrome (DubS) is considered a recognizable syndrome characterized by a distinctive facial appearance and deficits in growth and development. There have been over 200 individuals reported with Dubowitz or a "Dubowitz-like" condition, although no single gene has been implicated as responsible for its cause. We have performed exome (ES) or genome sequencing (GS) for 31 individuals clinically diagnosed with DubS. After genome-wide sequencing, rare variant filtering and computational and Mendelian genomic analyses, a presumptive molecular diagnosis was made in 13/27 (48\%) families. The molecular diagnoses included biallelic variants in SKIV2L, SLC35C1, BRCA1, NSUN2; de novo variants in ARID1B, ARID1A, CREBBP, POGZ, TAF1, HDAC8, and copy-number variation at1p36.11(ARID1A), 8q22.2(VPS13B), Xp22, and Xq13(HDAC8). Variants of unknown significance in known disease genes, and also in genes of uncertain significance, were observed in 7/27 (26\%) additional families. Only one gene, HDAC8, could explain the phenotype in more than one family (N = 2). All but two of the genomic diagnoses were for genes discovered, or for conditions recognized, since the introduction of next-generation sequencing. Overall, the DubS-like clinical phenotype is associated with extensive locus heterogeneity and the molecular diagnoses made are for emerging clinical conditions sharing characteristic features that overlap the DubS phenotype.

}, issn = {1552-4833}, doi = {10.1002/ajmg.a.61926}, author = {Dyment, David A and O{\textquoteright}Donnell-Luria, Anne and Agrawal, Pankaj B and Coban Akdemir, Zeynep and Aleck, Kyrieckos A and Antaki, Danny and Al Sharhan, Hind and Au, Ping-Yee B and Aydin, Hatip and Beggs, Alan H and Bilguvar, Kaya and Boerwinkle, Eric and Brand, Harrison and Brownstein, Catherine A and Buyske, Steve and Chodirker, Bernard and Choi, Jungmin and Chudley, Albert E and Clericuzio, Carol L and Cox, Gerald F and Curry, Cynthia and de Boer, Elke and de Vries, Bert B A and Dunn, Kathryn and Dutmer, Cullen M and England, Eleina M and Fahrner, Jill A and Geckinli, Bilgen B and Genetti, Casie A and Gezdirici, Alper and Gibson, William T and Gleeson, Joseph G and Greenberg, Cheryl R and Hall, April and Hamosh, Ada and Hartley, Taila and Jhangiani, Shalini N and Karaca, Ender and Kernohan, Kristin and Lauzon, Julie L and Lewis, M E Suzanne and Lowry, R Brian and L{\'o}pez-Gir{\'a}ldez, Francesc and Matise, Tara C and McEvoy-Venneri, Jennifer and McInnes, Brenda and Mhanni, Aziz and Garcia Minaur, Sixto and Moilanen, Jukka and Nguyen, An and Nowaczyk, Malgorzata J M and Posey, Jennifer E and {\~O}unap, Katrin and Pehlivan, Davut and Pajusalu, Sander and Penney, Lynette S and Poterba, Timothy and Prontera, Paolo and Doriqui, Maria Juliana Rodovalho and Sawyer, Sarah L and Sobreira, Nara and Stanley, Valentina and Torun, Deniz and Wargowski, David and Witmer, P Dane and Wong, Isaac and Xing, Jinchuan and Zaki, MAH S and Zhang, Yeting and Boycott, Kym M and Bamshad, Michael J and Nickerson, Deborah A and Blue, Elizabeth E and Innes, A Micheil} } @article {1000, title = {A DNA repair disorder caused by de novo monoallelic DDB1 variants is associated with a neurodevelopmental syndrome.}, journal = {Am J Hum Genet}, volume = {108}, year = {2021}, month = {2021 04 01}, pages = {749-756}, abstract = {

The DNA damage-binding protein 1 (DDB1) is part of the CUL4-DDB1 ubiquitin E3 ligase complex (CRL4), which is essential for DNA repair, chromatin remodeling, DNA replication, and signal transduction. Loss-of-function variants in genes encoding the complex components CUL4 and PHIP have been reported to cause syndromic intellectual disability with hypotonia and obesity, but no phenotype has been reported in association with DDB1 variants. Here, we report eight unrelated individuals, identified through Matchmaker Exchange, with de novo monoallelic variants in DDB1, including one recurrent variant in four individuals. The affected individuals have a consistent phenotype of hypotonia, mild to moderate intellectual disability, and similar facies, including horizontal or slightly bowed eyebrows, deep-set eyes, full cheeks, a short nose, and large, fleshy and forward-facing earlobes, demonstrated in the composite face generated from the cohort. Digital anomalies, including brachydactyly and syndactyly, were common. Three older individuals have obesity. We show that cells derived from affected individuals have altered DDB1 function resulting in abnormal DNA damage signatures and histone methylation following UV-induced DNA damage. Overall, our study adds to the growing family of neurodevelopmental phenotypes mediated by disruption of the CRL4 ubiquitin ligase pathway and begins to delineate the phenotypic and molecular effects of DDB1 misregulation.

}, keywords = {Adolescent, Alleles, Child, Child, Preschool, DNA Repair, DNA-Binding Proteins, Female, Humans, Male, Mutation, Neurodevelopmental Disorders, Phenotype, Syndrome}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2021.03.007}, author = {White, Susan M and Bhoj, Elizabeth and Nellaker, Christoffer and Lachmeijer, Augusta M A and Marshall, Aren E and Boycott, Kym M and Li, Dong and Smith, Wendy and Hartley, Taila and McBride, Arran and Ernst, Michelle E and May, Alison S and Wieczorek, Dagmar and Abou Jamra, Rami and Koch-Hogrebe, Margarete and {\~O}unap, Katrin and Pajusalu, Sander and van Gassen, K L I and Sadedin, Simon and Ellingwood, Sara and Tan, Tiong Yang and Christodoulou, John and Barea, Jaime and Lockhart, Paul J and Nezarati, Marjan M and Kernohan, Kristin D} } @article {1022, title = {POLRMT mutations impair mitochondrial transcription causing neurological disease.}, journal = {Nat Commun}, volume = {12}, year = {2021}, month = {2021 02 18}, pages = {1135}, abstract = {

While >300 disease-causing variants have been identified in the mitochondrial DNA (mtDNA) polymerase γ, no mitochondrial phenotypes have been associated with POLRMT, the RNA polymerase responsible for transcription of the mitochondrial genome. Here, we characterise the clinical and molecular nature of POLRMT variants in eight individuals from seven unrelated families. Patients present with global developmental delay, hypotonia, short stature, and speech/intellectual disability in childhood; one subject displayed an indolent progressive external ophthalmoplegia phenotype. Massive parallel sequencing of all subjects identifies recessive and dominant variants in the POLRMT gene. Patient fibroblasts have a defect in mitochondrial mRNA synthesis, but no mtDNA deletions or copy number abnormalities. The in vitro characterisation of the recombinant POLRMT mutants reveals variable, but deleterious effects on mitochondrial transcription. Together, our in vivo and in vitro functional studies of POLRMT variants establish defective mitochondrial transcription as an important disease mechanism.

}, keywords = {Adolescent, Adult, Child, DNA, Mitochondrial, DNA-Directed RNA Polymerases, Female, Fibroblasts, Humans, Infant, Male, Mitochondria, Mutation, Nervous System Diseases, Oxidative Phosphorylation, Pedigree, Protein Domains, Protein Subunits, RNA, Messenger, Transcription, Genetic, Young Adult}, issn = {2041-1723}, doi = {10.1038/s41467-021-21279-0}, author = {Ol{\'a}hov{\'a}, Monika and Peter, Bradley and Szilagyi, Zsolt and Diaz-Maldonado, Hector and Singh, Meenakshi and Sommerville, Ewen W and Blakely, Emma L and Collier, Jack J and Hoberg, Emily and Str{\'a}neck{\'y}, Viktor and Hartmannov{\'a}, Hana and Bleyer, Anthony J and McBride, Kim L and Bowden, Sasigarn A and Korandov{\'a}, Zuzana and Pecinov{\'a}, Alena and Ropers, Hans-Hilger and Kahrizi, Kimia and Najmabadi, Hossein and Tarnopolsky, Mark A and Brady, Lauren I and Weaver, K Nicole and Prada, Carlos E and {\~O}unap, Katrin and Wojcik, Monica H and Pajusalu, Sander and Syeda, Safoora B and Pais, Lynn and Estrella, Elicia A and Bruels, Christine C and Kunkel, Louis M and Kang, Peter B and Bonnen, Penelope E and Mr{\'a}{\v c}ek, Tom{\'a}{\v s} and Kmoch, Stanislav and Gorman, Gr{\'a}inne S and Falkenberg, Maria and Gustafsson, Claes M and Taylor, Robert W} } @article {769, title = {Delineation of a Human Mendelian Disorder of the DNA Demethylation Machinery: TET3 Deficiency.}, journal = {Am J Hum Genet}, volume = {106}, year = {2020}, month = {2020 02 06}, pages = {234-245}, abstract = {

Germline pathogenic variants in chromatin-modifying enzymes are a common cause of pediatric developmental disorders. These enzymes catalyze reactions that regulate epigenetic inheritance via histone post-translational modifications and DNA methylation. Cytosine methylation (5-methylcytosine [5mC]) of DNA is the quintessential epigenetic mark, yet no human Mendelian disorder of DNA demethylation has yet been delineated. Here, we describe in detail a Mendelian disorder caused by the disruption of DNA demethylation. TET3 is a methylcytosine dioxygenase that initiates DNA demethylation during early zygote formation, embryogenesis, and neuronal differentiation and is intolerant to haploinsufficiency in mice and humans. We identify and characterize 11 cases of human TET3 deficiency in eight families with the common phenotypic features of intellectual disability and/or global developmental delay; hypotonia; autistic traits; movement disorders; growth abnormalities; and facial dysmorphism. Mono-allelic frameshift and nonsense variants in TET3 occur throughout the coding region. Mono-allelic and bi-allelic missense variants localize to conserved residues; all but one such variant occur within the catalytic domain, and most display hypomorphic function in an assay of catalytic activity. TET3 deficiency and other Mendelian disorders of the epigenetic machinery show substantial phenotypic overlap, including features of intellectual disability and abnormal growth, underscoring shared disease mechanisms.

}, keywords = {Adult, Amino Acid Sequence, Autistic Disorder, Child, Child, Preschool, Developmental Disabilities, Dioxygenases, DNA Demethylation, Embryonic Development, Female, Gene Expression Regulation, Developmental, Growth Disorders, Humans, Infant, Male, Middle Aged, Movement Disorders, Pedigree, Protein Conformation, Sequence Homology, Young Adult}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2019.12.007}, author = {Beck, David B and Petracovici, Ana and He, Chongsheng and Moore, Hannah W and Louie, Raymond J and Ansar, Muhammad and Douzgou, Sofia and Sithambaram, Sivagamy and Cottrell, Trudie and Santos-Cortez, Regie Lyn P and Prijoles, Eloise J and Bend, Renee and Keren, Boris and Mignot, Cyril and Nougues, Marie-Christine and {\~O}unap, Katrin and Reimand, Tiia and Pajusalu, Sander and Zahid, Muhammad and Saqib, Muhammad Arif Nadeem and Buratti, Julien and Seaby, Eleanor G and McWalter, Kirsty and Telegrafi, Aida and Baldridge, Dustin and Shinawi, Marwan and Leal, Suzanne M and Schaefer, G Bradley and Stevenson, Roger E and Banka, Siddharth and Bonasio, Roberto and Fahrner, Jill A} } @article {748, title = {Genome sequencing identifies a homozygous inversion disrupting QDPR as a cause for dihydropteridine reductase deficiency.}, journal = {Mol Genet Genomic Med}, volume = {8}, year = {2020}, month = {2020 04}, pages = {e1154}, abstract = {

BACKGROUND: Dihydropteridine reductase (DHPR) is one of the key enzymes for maintaining in the organism the supply of tetrahydrobiopterin (BH ), an essential cofactor for aromatic amino acid hydroxylases. Its dysfunction causes the condition of hyperphenylalaninemia together with the lack of neurotransmitters.

METHODS: We report a patient with biochemically diagnosed DHPR deficiency, with extensive molecular investigations undertaken to detect variations in quinoid dihydropteridine reductase (QDPR) gene. Sanger sequencing of QDPR coding regions, exome sequencing, QDPR mRNA PCR, and karyotyping were followed by trio genome sequencing.

RESULTS: Short-read genome sequencing revealed a homozygous 9-Mb inversion disrupting QDPR. Structural variant breakpoints in chromosome 4 were located to intron 2 of QDPR at Chr4(GRCh38):g.17505522 and in intron 8 of the ACOX3 gene, Chr4(GRCh38):g.8398067). Both nonrelated parents carried the variant in heterozygous state. The inversion was not present in gnomAD structural variant database.

CONCLUSION: Identification of the exact breakpoints now allows further straightforward molecular genetic testing of potential carriers of the inversion. This study extends the pathogenic variant spectrum of DHPR deficiency and highlights the role of structural variants in recessive metabolic disorders. To our knowledge, this is the first report on a large, canonical (rather than complex) homozygous pathogenic inversion detected by genome sequencing.

}, keywords = {Acyl-CoA Oxidase, Child, Chromosome Breakpoints, Chromosome Inversion, Chromosomes, Human, Pair 4, Female, Genetic Testing, Homozygote, Humans, Phenylketonurias, Whole Exome Sequencing}, issn = {2324-9269}, doi = {10.1002/mgg3.1154}, author = {Lillev{\"a}li, Hardo and Pajusalu, Sander and Wojcik, Monica H and Goodrich, Julia and Collins, Ryan L and Murumets, {\"U}lle and Tammur, Pille and Blau, Nenad and Lillev{\"a}li, Kersti and {\~O}unap, Katrin} } @article {749, title = {A missense mutation in the catalytic domain of O-GlcNAc transferase links perturbations in protein O-GlcNAcylation to X-linked intellectual disability.}, journal = {FEBS Lett}, volume = {594}, year = {2020}, month = {2020 02}, pages = {717-727}, abstract = {

X-linked intellectual disabilities (XLID) are common developmental disorders. The enzyme O-GlcNAc transferase encoded by OGT, a recently discovered XLID gene, attaches O-GlcNAc to nuclear and cytoplasmic proteins. As few missense mutations have been described, it is unclear what the aetiology of the patient phenotypes is. Here, we report the discovery of a missense mutation in the catalytic domain of OGT in an XLID patient. X-ray crystallography reveals that this variant leads to structural rearrangements in the catalytic domain. The mutation reduces in~vitro OGT activity on substrate peptides/protein. Mouse embryonic stem cells carrying the mutation reveal reduced O-GlcNAcase (OGA) and global O-GlcNAc levels. These data suggest a direct link between changes in the O-GlcNAcome and intellectual disability observed in patients carrying OGT mutations.

}, keywords = {Animals, Catalytic Domain, Cell Line, Glycosylation, Humans, Intellectual Disability, Mice, Models, Molecular, Mutation, Missense, N-Acetylglucosaminyltransferases}, issn = {1873-3468}, doi = {10.1002/1873-3468.13640}, author = {Pravata, Veronica M and Gundogdu, Mehmet and Bartual, Sergio G and Ferenbach, Andrew T and Stavridis, Marios and {\~O}unap, Katrin and Pajusalu, Sander and {\v Z}ordania, Riina and Wojcik, Monica H and van Aalten, Daan M F} } @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 {726, title = {PEHO syndrome caused by compound heterozygote variants in ZNHIT3 gene.}, journal = {Eur J Med Genet}, volume = {63}, year = {2020}, month = {2020 Feb}, pages = {103660}, abstract = {

PEHO syndrome is characterized by Progressive Encephalopathy with Edema, Hypsarrhythmia, and Optic atrophy, which was first described in Finnish patients. A homozygous missense substitution p.Ser31Leu in ZNHIT3 was recently identified as the primary cause of PEHO syndrome in Finland. Variants in ZNHIT3 have not been identified in patients with PEHO or PEHO-like syndrome in other populations. It has therefore been suggested that PEHO syndrome caused by ZNHIT3 variants does not occur outside of the Finnish population. We describe the first patient outside Finland who carries compound heterozygous variants in ZNHIT3 gene causing PEHO syndrome. Trio genome sequencing was carried out and the identified variants were confirmed by Sanger sequencing. The patient filled all diagnostic clinical criteria of PEHO syndrome. We identified biallelic missense variants in ZNHIT3 gene: the c.92C > T p.(Ser31Leu) variant (NM_004773.3), which is described previously as causing PEHO syndrome and the second novel variant c.41G > T p.(Cys14Phe). There are only eight heterozygous carriers of c.41G > T variant in the gnomAD database and it is predicted damaging by multiple in silico algorithms. The ZNHIT3-associated PEHO syndrome exists outside of the Finnish population.

}, keywords = {Brain Edema, Databases, Genetic, Edema, Epileptic Syndromes, Female, Finland, Heterozygote, Humans, Infant, Newborn, Mutation, Missense, Neurodegenerative Diseases, Nuclear Proteins, Optic Atrophy, Phenotype, Spasms, Infantile, Transcription Factors, Whole Exome Sequencing, Whole Genome Sequencing}, issn = {1878-0849}, doi = {10.1016/j.ejmg.2019.04.017}, author = {{\~O}unap, Katrin and Muru, Kai and {\~O}iglane-Shlik, Eve and Ilves, Pilvi and Pajusalu, Sander and Kuus, Imbi and Wojcik, Monica H and Reimand, Tiia} } @article {797, title = {A three-year follow-up study evaluating clinical utility of exome sequencing and diagnostic potential of reanalysis.}, journal = {NPJ Genom Med}, volume = {5}, year = {2020}, month = {2020}, pages = {37}, abstract = {

Exome sequencing (ES) has become one of the important diagnostic tools in clinical genetics with a reported diagnostic rate of 25-58\%. Many studies have illustrated the diagnostic and immediate clinical impact of ES. However, up to 75\% of individuals remain undiagnosed and there is scarce evidence supporting clinical utility beyond a follow-up period of >1 year. This is a 3-year follow-up analysis to our previous publication by Mak et al. ( 3:19, 2018), to evaluate the long-term clinical utility of ES and the diagnostic potential of exome reanalysis. The diagnostic yield of the initial study was 41\% (43/104). Exome reanalysis in 46 undiagnosed individuals has achieved 12 new diagnoses. The additional yield compared with the initial analysis was at least 12\% (increased from 41\% to at least 53\%). After a median follow-up period of 3.4 years, change in clinical management was observed in 72.2\% of the individuals (26/36), leading to positive change in clinical outcome in four individuals (11\%). There was a minimum healthcare cost saving of HKD$152,078 (USD$19,497; {\texteuro}17,282) annually for these four individuals. There were a total of six pregnancies from five families within the period. Prenatal diagnosis was performed in four pregnancies; one fetus was affected and resulted in termination. None of the parents underwent preimplantation genetic diagnosis. This 3-year follow-up study demonstrated the long-term clinical utility of ES at individual, familial and health system level, and the promising diagnostic potential of subsequent reanalysis. This highlights the benefits of implementing ES and regular reanalysis in the clinical setting.

}, issn = {2056-7944}, doi = {10.1038/s41525-020-00144-x}, author = {Fung, Jasmine L F and Yu, Mullin H C and Huang, Shushu and Chung, Claudia C Y and Chan, Marcus C Y and Pajusalu, Sander and Mak, Christopher C Y and Hui, Vivian C C and Tsang, Mandy H Y and Yeung, Kit San and Lek, Monkol and Chung, Brian H Y} } @article {687, title = {Aberrant Function of the C-Terminal Tail of HIST1H1E Accelerates Cellular Senescence and Causes Premature Aging.}, journal = {Am J Hum Genet}, volume = {105}, year = {2019}, month = {2019 Sep 05}, pages = {493-508}, abstract = {

Histones mediate dynamic packaging of nuclear DNA in chromatin, a process that is precisely controlled to guarantee efficient compaction of the genome and proper chromosomal segregation during cell division and to accomplish DNA replication, transcription, and repair. Due to the important structural and regulatory roles played by histones, it is not surprising that histone functional dysregulation or aberrant levels of histones can have severe consequences for multiple cellular processes and ultimately might affect development or contribute to cell transformation. Recently, germline frameshift mutations involving the C-terminal tail of HIST1H1E, which is a widely expressed member of the linker histone family and facilitates higher-order chromatin folding, have been causally linked to an as-yet poorly defined syndrome that includes intellectual disability. We report that these mutations result in stable proteins that reside in the nucleus, bind to chromatin, disrupt proper compaction of DNA, and are associated with a specific methylation pattern. Cells expressing these mutant proteins have a dramatically reduced proliferation rate and competence, hardly enter into the S phase, and undergo accelerated senescence. Remarkably, clinical assessment of a relatively large cohort of subjects sharing these mutations revealed a premature aging phenotype as a previously unrecognized feature of the disorder. Our findings identify a direct link between aberrant chromatin remodeling, cellular senescence, and accelerated aging.

}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2019.07.007}, author = {Flex, Elisabetta and Martinelli, Simone and Van Dijck, Anke and Ciolfi, Andrea and Cecchetti, Serena and Coluzzi, Elisa and Pannone, Luca and Andreoli, Cristina and Radio, Francesca Clementina and Pizzi, Simone and Carpentieri, Giovanna and Bruselles, Alessandro and Catanzaro, Giuseppina and Pedace, Lucia and Miele, Evelina and Carcarino, Elena and Ge, Xiaoyan and Chijiwa, Chieko and Lewis, M E Suzanne and Meuwissen, Marije and Kenis, Sandra and Van der Aa, Nathalie and Larson, Austin and Brown, Kathleen and Wasserstein, Melissa P and Skotko, Brian G and Begtrup, Amber and Person, Richard and Karayiorgou, Maria and Roos, J Louw and Van Gassen, Koen L and Koopmans, Marije and Bijlsma, Emilia K and Santen, Gijs W E and Barge-Schaapveld, Daniela Q C M and Ruivenkamp, Claudia A L and Hoffer, Mariette J V and Lalani, Seema R and Streff, Haley and Craigen, William J and Graham, Brett H and van den Elzen, Annette P M and Kamphuis, Daan J and {\~O}unap, Katrin and Reinson, Karit and Pajusalu, Sander and Wojcik, Monica H and Viberti, Clara and Di Gaetano, Cornelia and Bertini, Enrico and Petrucci, Simona and De Luca, Alessandro and Rota, Rossella and Ferretti, Elisabetta and Matullo, Giuseppe and Dallapiccola, Bruno and Sgura, Antonella and Walkiewicz, Magdalena and Kooy, R Frank and Tartaglia, Marco} } @article {670, title = {CTCF variants in 39 individuals with a variable neurodevelopmental disorder broaden the mutational and clinical spectrum.}, journal = {Genet Med}, volume = {21}, year = {2019}, month = {2019 12}, pages = {2723-2733}, abstract = {

PURPOSE: Pathogenic variants in the chromatin organizer CTCF were previously reported in seven individuals with a neurodevelopmental disorder (NDD).

METHODS: Through international collaboration we collected data from 39 subjects with variants in CTCF. We performed transcriptome analysis on RNA from blood samples and utilized Drosophila melanogaster to investigate the impact of Ctcf dosage alteration on nervous system development and function.

RESULTS: The individuals in our cohort carried 2 deletions, 8 likely gene-disruptive, 2 splice-site, and 20 different missense variants, most of them de novo. Two cases were familial. The associated phenotype was of variable severity extending from mild developmental delay or normal IQ to severe intellectual disability. Feeding difficulties and behavioral abnormalities were common, and variable other findings including growth restriction and cardiac defects were observed. RNA-sequencing in five individuals identified 3828 deregulated genes enriched for known NDD genes and biological processes such as transcriptional regulation. Ctcf dosage alteration in Drosophila resulted in impaired gross neurological functioning and learning and memory deficits.

CONCLUSION: We significantly broaden the mutational and clinical spectrum ofCTCF-associated NDDs. Our data shed light onto the functional role of CTCF by identifying deregulated genes and show that Ctcf alterations result in nervous system defects in Drosophila.

}, issn = {1530-0366}, doi = {10.1038/s41436-019-0585-z}, author = {Konrad, Enrico D H and Nardini, Niels and Caliebe, Almuth and Nagel, Inga and Young, Dana and Horvath, Gabriella and Santoro, Stephanie L and Shuss, Christine and Ziegler, Alban and Bonneau, Dominique and Kempers, Marlies and Pfundt, Rolph and Legius, Eric and Bouman, Arjan and Stuurman, Kyra E and {\~O}unap, Katrin and Pajusalu, Sander and Wojcik, Monica H and Vasileiou, Georgia and Le Guyader, Gwena{\"e}l and Schnelle, Hege M and Berland, Siren and Zonneveld-Huijssoon, Evelien and Kersten, Simone and Gupta, Aditi and Blackburn, Patrick R and Ellingson, Marissa S and Ferber, Matthew J and Dhamija, Radhika and Klee, Eric W and McEntagart, Meriel and Lichtenbelt, Klaske D and Kenney, Amy and Vergano, Samantha A and Abou Jamra, Rami and Platzer, Konrad and Ella Pierpont, Mary and Khattar, Divya and Hopkin, Robert J and Martin, Richard J and Jongmans, Marjolijn C J and Chang, Vivian Y and Martinez-Agosto, Julian A and Kuismin, Outi and Kurki, Mitja I and Pietil{\"a}inen, Olli and Palotie, Aarno and Maarup, Timothy J and Johnson, Diana S and Venborg Pedersen, Katja and Laulund, Lone W and Lynch, Sally A and Blyth, Moira and Prescott, Katrina and Canham, Natalie and Ibitoye, Rita and Brilstra, Eva H and Shinawi, Marwan and Fassi, Emily and Sticht, Heinrich and Gregor, Anne and Van Esch, Hilde and Zweier, Christiane} } @article {675, title = {A retrospective analysis of the prevalence of imprinting disorders in Estonia from 1998 to 2016.}, journal = {Eur J Hum Genet}, volume = {27}, year = {2019}, month = {2019 Nov}, pages = {1649-1658}, abstract = {

Imprinting disorders (ImpDis) represent a small group of rare congenital diseases primarily affecting growth, development, and the hormonal and metabolic systems. The aim of present study was to identify the prevalence of the ImpDis in Estonia, to describe trends in the live birth prevalence of these disorders between 1998 and 2016, and to compare the results with previously published data. We retrospectively reviewed the records of all Estonian patients since 1998 with both molecularly and clinically diagnosed ImpDis. A prospective study was also conducted, in which all patients with clinical suspicion for an ImpDis were molecularly analyzed. Eighty-seven individuals with ImpDis were identified. Twenty-seven (31\%) of them had Prader-Willi syndrome (PWS), 15 (17\%) had Angelman syndrome (AS), 15 (17\%) had Silver-Russell syndrome (SRS), 12 (14\%) had Beckwith-Wiedemann syndrome (BWS), 10 (11\%) had pseudo- or pseudopseudohypoparathyroidism, four had central precocious puberty, two had Temple syndrome, one had transient neonatal diabetes mellitus, and one had myoclonus-dystonia syndrome. One third of SRS and BWS cases fulfilled the diagnostic criteria for these disorders, but tested negative for genetic abnormalities. Seventy-six individuals were alive as of January 1, 2018, indicating the total prevalence of ImpDis in Estonia is 5.8/100,000 (95\% CI 4.6/100,000-7.2/100,000). The minimum live birth prevalence of all ImpDis in Estonia in 2004-2016 was 1/3,462, PWS 1/13,599, AS 1/27,198, BWS 1/21,154, SRS 1/15,866, and PHP/PPHP 1/27,198. Our results are only partially consistent with previously published data. The worldwide prevalence of SRS and GNAS-gene-related ImpDis is likely underestimated and may be at least three times higher than expected.

}, issn = {1476-5438}, doi = {10.1038/s41431-019-0446-x}, author = {Yakoreva, Maria and Kahre, Tiina and {\v Z}ordania, Riina and Reinson, Karit and Teek, Rita and Tillmann, Vallo and Peet, Aleksandr and {\~O}iglane-Shlik, Eve and Pajusalu, Sander and Murumets, {\"U}lle and Vals, Mari-Anne and Mee, Pille and Wojcik, Monica H and {\~O}unap, Katrin} } @article {491, title = {Dual Molecular Effects of Dominant RORA Mutations Cause Two Variants of Syndromic Intellectual Disability with Either Autism or Cerebellar Ataxia.}, journal = {Am J Hum Genet}, volume = {102}, year = {2018}, month = {2018 05 03}, pages = {744-759}, abstract = {

RORα, the RAR-related orphan nuclear receptor alpha, is essential for cerebellar development. The spontaneous mutant mouse staggerer, with an ataxic gait caused by neurodegeneration of cerebellar Purkinje cells, was discovered two decades ago to result from homozygous intragenic Rora deletions. However, RORA mutations were hitherto undocumented in humans. Through a multi-centric collaboration, we identified three copy-number variant deletions (two de novo and one dominantly inherited in three generations), one de novo disrupting duplication, and nine de novo point mutations (three truncating, one canonical splice site, and five missense mutations) involving RORA in 16 individuals from 13 families with variable neurodevelopmental delay and intellectual disability (ID)-associated autistic features, cerebellar ataxia, and epilepsy. Consistent with the human and mouse data, disruption of the D.~rerio ortholog, roraa, causes significant reduction in the size of the developing cerebellum. Systematic in~vivo complementation studies showed that, whereas wild-type human RORA mRNA could complement the cerebellar pathology, missense variants had two distinct pathogenic mechanisms of either haploinsufficiency or a dominant toxic effect according to their localization in the ligand-binding or DNA-binding domains, respectively. This dichotomous direction of effect is likely relevant to the phenotype in humans: individuals with loss-of-function variants leading to haploinsufficiency show ID with autistic features, while individuals with de novo dominant toxic variants present with ID, ataxia, and cerebellar atrophy. Our combined genetic and functional data highlight the complex mutational landscape at the human RORA locus and suggest that dual mutational effects likely determine phenotypic outcome.

}, keywords = {Adolescent, Adult, Aged, 80 and over, Alleles, Animals, Autistic Disorder, Brain, Cerebellar Ataxia, Child, Child, Preschool, Disease Models, Animal, DNA Copy Number Variations, Female, Genes, Dominant, Genetic Complementation Test, Humans, Intellectual Disability, Larva, Magnetic Resonance Imaging, Male, Middle Aged, Mutation, Missense, Nuclear Receptor Subfamily 1, Group F, Member 1, Purkinje Cells, Syndrome, Zebrafish}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2018.02.021}, author = {Guissart, Claire and Latypova, X{\'e}nia and Rollier, Paul and Khan, Tahir N and Stamberger, Hannah and McWalter, Kirsty and Cho, Megan T and Kjaergaard, Susanne and Weckhuysen, Sarah and Lesca, Gaetan and Besnard, Thomas and {\~O}unap, Katrin and Schema, Lynn and Chiocchetti, Andreas G and McDonald, Marie and de Bellescize, Julitta and Vincent, Marie and Van Esch, Hilde and Sattler, Shannon and Forghani, Irman and Thiffault, Isabelle and Freitag, Christine M and Barbouth, Deborah Sara and Cadieux-Dion, Maxime and Willaert, Rebecca and Guillen Sacoto, Maria J and Safina, Nicole P and Dubourg, Christ{\`e}le and Grote, Lauren and Carr{\'e}, Wilfrid and Saunders, Carol and Pajusalu, Sander and Farrow, Emily and Boland, Anne and Karlowicz, Danielle Hays and Deleuze, Jean-Fran{\c c}ois and Wojcik, Monica H and Pressman, Rena and Isidor, Bertrand and Vogels, Annick and Van Paesschen, Wim and Al-Gazali, Lihadh and Al Shamsi, Aisha Mohamed and Claustres, Mireille and Pujol, Aurora and Sanders, Stephan J and Rivier, Fran{\c c}ois and Leboucq, Nicolas and Cogn{\'e}, Benjamin and Sasorith, Souphatta and Sanlaville, Damien and Retterer, Kyle and Odent, Sylvie and Katsanis, Nicholas and B{\'e}zieau, St{\'e}phane and Koenig, Michel and Davis, Erica E and Pasquier, Laurent and K{\"u}ry, S{\'e}bastien} }