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Browsing by Subject "Haploinsufficiency"
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Item A cross-disorder dosage sensitivity map of the human genome(Elsevier, 2022) Collins, Ryan L.; Glessner, Joseph T.; Porcu, Eleonora; Lepamets, Maarja; Brandon, Rhonda; Lauricella, Christopher; Han, Lide; Morley, Theodore; Niestroj, Lisa-Marie; Ulirsch, Jacob; Everett, Selin; Howrigan, Daniel P.; Boone, Philip M.; Fu, Jack; Karczewski, Konrad J.; Kellaris, Georgios; Lowther, Chelsea; Lucente, Diane; Mohajeri, Kiana; Nõukas, Margit; Nuttle, Xander; Samocha, Kaitlin E.; Trinh, Mi; Ullah, Farid; Võsa, Urmo; Epi25 Consortium; Estonian Biobank Research Team; Hurles, Matthew E.; Aradhya, Swaroop; Davis, Erica E.; Finucane, Hilary; Gusella, James F.; Janze, Aura; Katsanis, Nicholas; Matyakhina, Ludmila; Neale, Benjamin M.; Sanders, David; Warren, Stephanie; Hodge, Jennelle C.; Lal, Dennis; Ruderfer, Douglas M.; Meck, Jeanne; Mägi, Reedik; Esko, Tõnu; Reymond, Alexandre; Kutalik, Zoltán; Hakonarson, Hakon; Sunyaev, Shamil; Brand, Harrison; Talkowski, Michael E.; Medical and Molecular Genetics, School of MedicineRare copy-number variants (rCNVs) include deletions and duplications that occur infrequently in the global human population and can confer substantial risk for disease. In this study, we aimed to quantify the properties of haploinsufficiency (i.e., deletion intolerance) and triplosensitivity (i.e., duplication intolerance) throughout the human genome. We harmonized and meta-analyzed rCNVs from nearly one million individuals to construct a genome-wide catalog of dosage sensitivity across 54 disorders, which defined 163 dosage sensitive segments associated with at least one disorder. These segments were typically gene dense and often harbored dominant dosage sensitive driver genes, which we were able to prioritize using statistical fine-mapping. Finally, we designed an ensemble machine-learning model to predict probabilities of dosage sensitivity (pHaplo & pTriplo) for all autosomal genes, which identified 2,987 haploinsufficient and 1,559 triplosensitive genes, including 648 that were uniquely triplosensitive. This dosage sensitivity resource will provide broad utility for human disease research and clinical genetics.Item De Novo and Inherited Loss-of-Function Variants in TLK2: Clinical and Genotype-Phenotype Evaluation of a Distinct Neurodevelopmental Disorder(Elsevier, 2018-06-07) Reijnders, Margot R.F.; Miller, Kerry A.; Alvi, Mohsan; Goos, Jacqueline A.C.; Lees, Melissa M.; de Burca, Anna; Henderson, Alex; Kraus, Alison; Mikat, Barbara; de Vries, Bert B.A.; Isidor, Bertrand; Kerr, Bronwyn; Marcelis, Carlo; Schluth-Bolard, Caroline; Deshpande, Charu; Ruivenkamp, Claudia A.L.; Wieczorek, Dagmar; Baralle, Diana; Blair, Edward M.; Engels, Hartmut; Lüdecke, Hermann-Josef; Eason, Jacqueline; Santen, Gijs W.E.; Clayton-Smith, Jill; Chandler, Kate; Tatton-Brown, Katrina; Payne, Katelyn; Helbig, Katherine; Radtke, Kelly; Nugent, Kimberly M.; Cremer, Kirsten; Strom, Tim M.; Bird, Lynne M.; Sinnema, Margje; Bitner-Glindzicz, Maria; van Dooren, Marieke F.; Alders, Marielle; Koopmans, Marije; Brick, Lauren; Kozenko, Mariya; Harline, Megan L.; Klaassens, Merel; Steinraths, Michelle; Cooper, Nicola S.; Edery, Patrick; Yap, Patrick; Terhal, Paulien A.; van der Spek, Peter J.; Lakeman, Phillis; Taylor, Rachel L.; Littlejohn, Rebecca O.; Pfundt, Rolph; Mercimek-Andrews, Saadet; Stegmann, Alexander P.A.; Kant, Sarina G.; McLean, Scott; Joss, Shelagh; Swagemakers, Sigrid M.A.; Douzgou, Sofia; Wall, Steven A.; Küry, Sebastian; Calpena, Eduardo; Koelling, Nils; McGowan, Simon J.; Twigg, Stephen R.F.; Mathijssen, Irene M.J.; Nellaker, Christoffer; Brunner, Han G.; Wilkie, Andrew O.M.; Medical and Molecular Genetics, School of MedicineNext-generation sequencing is a powerful tool for the discovery of genes related to neurodevelopmental disorders (NDDs). Here, we report the identification of a distinct syndrome due to de novo or inherited heterozygous mutations in Tousled-like kinase 2 (TLK2) in 38 unrelated individuals and two affected mothers, using whole-exome and whole-genome sequencing technologies, matchmaker databases, and international collaborations. Affected individuals had a consistent phenotype, characterized by mild-borderline neurodevelopmental delay (86%), behavioral disorders (68%), severe gastro-intestinal problems (63%), and facial dysmorphism including blepharophimosis (82%), telecanthus (74%), prominent nasal bridge (68%), broad nasal tip (66%), thin vermilion of the upper lip (62%), and upslanting palpebral fissures (55%). Analysis of cell lines from three affected individuals showed that mutations act through a loss-of-function mechanism in at least two case subjects. Genotype-phenotype analysis and comparison of computationally modeled faces showed that phenotypes of these and other individuals with loss-of-function variants significantly overlapped with phenotypes of individuals with other variant types (missense and C-terminal truncating). This suggests that haploinsufficiency of TLK2 is the most likely underlying disease mechanism, leading to a consistent neurodevelopmental phenotype. This work illustrates the power of international data sharing, by the identification of 40 individuals from 26 different centers in 7 different countries, allowing the identification, clinical delineation, and genotype-phenotype evaluation of a distinct NDD caused by mutations in TLK2.Item De novo and inherited TCF20 pathogenic variants are associated with intellectual disability, dysmorphic features, hypotonia, and neurological impairments with similarities to Smith-Magenis syndrome(BMC, 2019-02-28) Vetrini, Francesco; McKee, Shane; Rosenfeld, Jill A.; Suri, Mohnish; Lewis, Andrea M.; Nugent, Kimberly Margaret; Roeder, Elizabeth; Littlejohn, Rebecca O.; Holder, Sue; Zhu, Wenmiao; Alaimo, Joseph T.; Graham, Brett; Harris, Jill M.; Gibson, James B.; Pastore, Matthew; McBride, Kim L.; Komara, Makanko; Al-Gazali, Lihadh; Al Shamsi, Aisha; Fanning, Elizabeth A.; Wierenga, Klaas J.; Scott, Daryl A.; Ben-Neriah, Ziva; Meiner, Vardiella; Cassuto, Hanoch; Elpeleg, Orly; Holder, J. Lloyd, Jr.; Burrage, Lindsay C.; Seaver, Laurie H.; Van Maldergem, Lionel; Mahida, Sonal; Soul, Janet S.; Marlatt, Margaret; Matyakhina, Ludmila; Vogt, Julie; Gold, June-Anne; Park, Soo-Mi; Varghese, Vinod; Lampe, Anne K.; Kumar, Ajith; Lees, Melissa; Holder-Espinasse, Muriel; McConnell, Vivienne; Bernhard, Birgitta; Blair, Ed; Harrison, Victoria; The DDD study; Muzny, Donna M.; Gibbs, Richard A.; Elsea, Sarah H.; Posey, Jennifer E.; Bi, Weimin; Lalani, Seema; Xia, Fan; Yang, Yaping; Eng, Christine M.; Lupski, James R.; Liu, Pengfei; Medical and Molecular Genetics, School of MedicineBACKGROUND: Neurodevelopmental disorders are genetically and phenotypically heterogeneous encompassing developmental delay (DD), intellectual disability (ID), autism spectrum disorders (ASDs), structural brain abnormalities, and neurological manifestations with variants in a large number of genes (hundreds) associated. To date, a few de novo mutations potentially disrupting TCF20 function in patients with ID, ASD, and hypotonia have been reported. TCF20 encodes a transcriptional co-regulator structurally related to RAI1, the dosage-sensitive gene responsible for Smith-Magenis syndrome (deletion/haploinsufficiency) and Potocki-Lupski syndrome (duplication/triplosensitivity). METHODS: Genome-wide analyses by exome sequencing (ES) and chromosomal microarray analysis (CMA) identified individuals with heterozygous, likely damaging, loss-of-function alleles in TCF20. We implemented further molecular and clinical analyses to determine the inheritance of the pathogenic variant alleles and studied the spectrum of phenotypes. RESULTS: We report 25 unique inactivating single nucleotide variants/indels (1 missense, 1 canonical splice-site variant, 18 frameshift, and 5 nonsense) and 4 deletions of TCF20. The pathogenic variants were detected in 32 patients and 4 affected parents from 31 unrelated families. Among cases with available parental samples, the variants were de novo in 20 instances and inherited from 4 symptomatic parents in 5, including in one set of monozygotic twins. Two pathogenic loss-of-function variants were recurrent in unrelated families. Patients presented with a phenotype characterized by developmental delay, intellectual disability, hypotonia, variable dysmorphic features, movement disorders, and sleep disturbances. CONCLUSIONS: TCF20 pathogenic variants are associated with a novel syndrome manifesting clinical characteristics similar to those observed in Smith-Magenis syndrome. Together with previously described cases, the clinical entity of TCF20-associated neurodevelopmental disorders (TAND) emerges from a genotype-driven perspective.Item Phenotypic Variability in Phelan-McDermid Syndrome and Its Putative Link to Environmental Factors(MDPI, 2022-03-17) Boccuto, Luigi; Mitz, Andrew; Abenavoli, Ludovico; Sarasua, Sara M.; Bennett, William; Rogers, Curtis; DuPont, Barbara; Phelan, Katy; Pediatrics, School of MedicinePhelan-McDermid syndrome (PMS) is a multi-systemic disorder characterized by both genetic and phenotypic variability. Genetic abnormalities causing PMS span from pathogenic variants of the SHANK3 gene to chromosomal rearrangements affecting the 22q13 region and leading to the loss of up to over nine megabases. The clinical presentation of individuals with PMS includes intellectual disability, neonatal hypotonia, delayed or absent speech, developmental delay, and minor dysmorphic facial features. Several other features may present with differences in age of onset and/or severity: seizures, autism, regression, sleep disorders, gastrointestinal problems, renal disorders, dysplastic toenails, and disrupted thermoregulation. Among the causes of this phenotypic variability, the size of the 22q13 deletion has effects that may be influenced by environmental factors interacting with haploinsufficiency or hemizygous variants of certain genes. Another mechanism linking environmental factors and phenotypic variability in PMS involves the loss of one copy of genes like BRD1 or CYP2D6, located at 22q13 and involved in the regulation of genomic methylation or pharmacokinetics, which are also influenced by external agents, such as diet and drugs. Overall, several non-mutually exclusive genetic and epigenetic mechanisms interact with environmental factors and may contribute to the clinical variability observed in individuals with PMS. Characterization of such factors will help to better manage this disorder.Item Skeletal health in DYRK1A syndrome(Frontiers Media, 2024-09-06) Otte, Elysabeth D.; Roper, Randall J.; Biology, School of ScienceDYRK1A syndrome results from a reduction in copy number of the DYRK1A gene, which resides on human chromosome 21 (Hsa21). DYRK1A has been implicated in the development of cognitive phenotypes associated with many genetic disorders, including Down syndrome (DS) and Alzheimer’s disease (AD). Additionally, overexpression of DYRK1A in DS has been implicated in the development of abnormal skeletal phenotypes in these individuals. Analyses of mouse models with Dyrk1a dosage imbalance (overexpression and underexpression) show skeletal deficits and abnormalities. Normalization of Dyrk1a copy number in an otherwise trisomic animal rescues some skeletal health parameters, and reduction of Dyrk1a copy number in an otherwise euploid (control) animal results in altered skeletal health measurements, including reduced bone mineral density (BMD) in the femur, mandible, and skull. However, little research has been conducted thus far on the implications of DYRK1A reduction on human skeletal health, specifically in individuals with DYRK1A syndrome. This review highlights the skeletal phenotypes of individuals with DYRK1A syndrome, as well as in murine models with reduced Dyrk1a copy number, and provides potential pathways altered by a reduction of DYRK1A copy number, which may impact skeletal health and phenotypes in these individuals. Understanding how decreased expression of DYRK1A in individuals with DYRK1A syndrome impacts bone health may increase awareness of skeletal traits and assist in the development of therapies to improve quality of life for these individuals.