Browsing by Author "Bird, Lynne M."
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Item Correction: Expanding the clinical phenotype of individuals with a 3-bp in-frame deletion of the NF1 gene (c.2970_2972del): an update of genotype–phenotype correlation(Elsevier, 2019-03) Koczkowska, Magdalena; Callens, Tom; Gomes, Alicia; Sharp, Angela; Chen, Yunjia; Hicks, Alesha D.; Aylsworth, Arthur S.; Azizi, Amedeo A.; Basel, Donald G.; Bellus, Gary; Bird, Lynne M.; Blazo, Maria A.; Burke, Leah W.; Cannon, Ashley; Collins, Felicity; DeFilippo, Colette; Denayer, Ellen; Digilio, Maria C.; Dills, Shelley K.; Dosa, Laura; Greenwood, Robert S.; Griffis, Cristin; Gupta, Punita; Hachen, Rachel K.; Hernández-Chico, Concepción; Janssens, Sandra; Jones, Kristi J.; Jordan, Justin T.; Kannu, Peter; Korf, Bruce R.; Lewis, Andrea M.; Listernick, Robert H.; Lonardo, Fortunato; Mahoney, Maurice J.; Ojeda, Mayra Martinez; McDonald, Marie T.; McDougall, Carey; Mendelsohn, Nancy; Miller, David T.; Mori, Mari; Oostenbrink, Rianne; Perreault, Sebastién; Pierpont, Mary Ella; Piscopo, Carmelo; Pond, Dinel A.; Randolph, Linda M.; Rauen, Katherine A.; Rednam, Surya; Rutledge, S. Lane; Saletti, Veronica; Schaefer, G. Bradley; Schorry, Elizabeth K.; Scott, Daryl A.; Shugar, Andrea; Siqveland, Elizabeth; Starr, Lois J.; Syed, Ashraf; Trapane, Pamela L.; Ullrich, Nicole J.; Wakefield, Emily G.; Walsh, Laurence E.; Wangler, Michael F.; Zackai, Elaine; Claes, Kathleen B.M.; Wimmer, Katharina; van Minkelen, Rick; De Luca, Alessandro; Martin, Yolanda; Legius, Eric; Messiaen, Ludwine M.; Neurology, School of MedicinePurpose: Neurofibromatosis type 1 (NF1) is characterized by a highly variable clinical presentation, but almost all NF1-affected adults present with cutaneous and/or subcutaneous neurofibromas. Exceptions are individuals heterozygous for the NF1 in-frame deletion, c.2970_2972del (p.Met992del), associated with a mild phenotype without any externally visible tumors. Methods: A total of 135 individuals from 103 unrelated families, all carrying the constitutional NF1 p.Met992del pathogenic variant and clinically assessed using the same standardized phenotypic checklist form, were included in this study. Results: None of the individuals had externally visible plexiform or histopathologically confirmed cutaneous or subcutaneous neurofi- bromas. We did not identify any complications, such as sympto-matic optic pathway gliomas (OPGs) or symptomatic spinal neurofibromas; however, 4.8% of individuals had nonoptic brain tumors, mostly low-grade and asymptomatic, and 38.8% had cognitive impairment/learning disabilities. In an individual with the NF1 constitutional c.2970_2972del and three astrocytomas, we provided proof that all were NF1-associated tumors given loss of heterozygosity at three intragenic NF1 microsatellite markers and c.2970_2972del. Conclusion: We demonstrate that individuals with the NF1 p.Met992del pathogenic variant have a mild NF1 phenotype lacking clinically suspected plexiform, cutaneous, or subcutaneous neurofi-bromas. However, learning difficulties are clearly part of the phenotypic presentation in these individuals and will require specialized care.Item Diazoxide Choline Extended-Release Tablet in People With Prader-Willi Syndrome: A Double-Blind, Placebo-Controlled Trial(Oxford University Press, 2023) Miller, Jennifer L.; Gevers, Evelien; Bridges, Nicola; Yanovski, Jack A.; Salehi, Parisa; Obrynba, Kathryn S.; Felner, Eric I.; Bird, Lynne M.; Shoemaker, Ashley H.; Angulo, Moris; Butler, Merlin G.; Stevenson, David; Abuzzahab, Jennifer; Barrett, Timothy; Lah, Melissa; Littlejohn, Elizabeth; Mathew, Verghese; Cowen, Neil M.; Bhatnagar, Anish; DESTINY PWS Investigators; Medical and Molecular Genetics, School of MedicineContext: Prader-Willi syndrome (PWS) is a rare neurobehavioral-metabolic disease caused by the lack of paternally expressed genes in the chromosome 15q11-q13 region, characterized by hypotonia, neurocognitive problems, behavioral difficulties, endocrinopathies, and hyperphagia resulting in severe obesity if not controlled. Objective: The primary end point was change from baseline in hyperphagia using the Hyperphagia Questionnaire for Clinical Trials (HQ-CT). Other end points included Global Impression Scores, and changes in body composition, behaviors, and hormones. Methods: In DESTINY PWS, a 13-week, randomized, double-blind, placebo-controlled, phase 3 trial, 127 participants with PWS aged 4 years and older with hyperphagia were randomly assigned 2:1 to diazoxide choline extended-release tablet (DCCR) or placebo. Results: DCCR did not significantly improve hyperphagia (HQ-CT least-square mean (LSmean) [SE] -5.94 [0.879] vs -4.27 [1.145]; P = .198), but did so in participants with severe hyperphagia (LSmean [SE] -9.67 [1.429] vs -4.26 [1.896]; P = .012). Two of 3 secondary end points were improved (Clinical Global Impression of Improvement [CGI-I]; P = .029; fat mass; P = .023). In an analysis of results generated pre-COVID, the primary (HQ-CT; P = .037) and secondary end points were all improved (CGI-I; P = .015; Caregiver Global Impression of Change; P = .031; fat mass; P = .003). In general, DCCR was well tolerated with 83.3% in the DCCR group experiencing a treatment-emergent adverse event and 73.8% in the placebo group (not significant). Conclusion: DCCR did not significantly improve hyperphagia in the primary analysis but did in participants with severe baseline hyperphagia and in the pre-COVID analysis. DCCR treatment was associated with significant improvements in body composition and clinician-reported outcomes.Item Diazoxide Choline Extended-Release Tablet in People with Prader-Willi Syndrome: Results from Long-Term Open-Label Study(Wiley, 2024) Miller, Jennifer L.; Gevers, Evelien; Bridges, Nicola; Yanovski, Jack A.; Salehi, Parisa; Obrynba, Kathryn S.; Felner, Eric I.; Bird, Lynne M.; Shoemaker, Ashley H.; Angulo, Moris; Butler, Merlin G.; Stevenson, David; Goldstone, Anthony P.; Wilding, John; Lah, Melissa; Shaikh, M. Guftar; Littlejohn, Elizabeth; Abuzzahab, M. Jennifer; Fleischman, Amy; Hirano, Patricia; Yen, Kristen; Cowen, Neil M.; Bhatnagar, Anish; C601/C602 Investigators; Medical and Molecular Genetics, School of MedicineObjective: This study assessed the effect of 1-year administration of diazoxide choline extended-release tablet (DCCR) on hyperphagia and other complications of Prader-Willi syndrome (PWS). Methods: The authors studied 125 participants with PWS, age ≥ 4 years, who were enrolled in the DESTINY PWS Phase 3 study and who received DCCR for up to 52 weeks in DESTINY PWS and/or its open-label extension. The primary efficacy endpoint was Hyperphagia Questionnaire for Clinical Trials (HQ-CT) score. Other endpoints included behavioral assessments, body composition, hormonal measures, and safety. Results: DCCR administration resulted in significant improvements in HQ-CT (mean [SE] -9.9 [0.77], p < 0.0001) and greater improvements in those with more severe baseline hyperphagia (HQ-CT > 22). Improvements were seen in aggression, anxiety, and compulsivity (all p < 0.0001). There were reductions in leptin, insulin, and insulin resistance, as well as a significant increase in adiponectin (all p < 0.004). Lean body mass was increased (p < 0.0001). Disease severity was reduced as assessed by clinician and caregiver (both p < 0.0001). Common treatment-emergent adverse events included hypertrichosis, peripheral edema, and hyperglycemia. Adverse events infrequently resulted in discontinuation (7.2%). Conclusions: DCCR administration to people with PWS was well tolerated and associated with broad-ranging improvements in the syndrome. Sustained administration of DCCR has the potential to reduce disease severity and the burden of care for families.Item A dyadic approach to the delineation of diagnostic entities in clinical genomics(Cell Press, 2021-01-07) Biesecker, Leslie G.; Adam, Margaret P.; Alkuraya, Fowzan S.; Amemiya, Anne R.; Bamshad, Michael J.; Beck, Anita E.; Bennett, James T.; Bird, Lynne M.; Carey, John C.; Chung, Brian; Clark, Robin D.; Cox, Timothy C.; Curry, Cynthia; Palko Dinulos, Mary Beth; Dobyns, William B.; Giampietro, Philip F.; Girisha, Katta M.; Glass, Ian A.; Graham, John M., Jr.; Gripp, Karen W.; Haldeman-Englert, Chad R.; Hall, Bryan D.; Innes, A. Micheil; Kalish, Jennifer M.; Keppler-Noreuil, Kim M.; Kosaki, Kenjiro; Kozel, Beth A.; Mirzaa, Ghayda M.; Mulvihill, John J.; Nowaczyk, Malgorzata J.M.; Pagon, Roberta A.; Retterer, Kyle; Rope, Alan F.; Sanchez-Lara, Pedro A.; Seaver, Laurie H.; Shieh, Joseph T.; Slavotinek, Anne M.; Sobering, Andrew K.; Stevens, Cathy A.; Stevenson, David A.; Tan, Tiong Yang; Tan, Wen-Hann; Tsai, Anne C.; Weaver, David D.; Williams, Marc S.; Zackai, Elaine; Zarate, Yuri A.; Medical and Molecular Genetics, School of MedicineThe delineation of disease entities is complex, yet recent advances in the molecular characterization of diseases provide opportunities to designate diseases in a biologically valid manner. Here, we have formalized an approach to the delineation of Mendelian genetic disorders that encompasses two distinct but inter-related concepts: (1) the gene that is mutated and (2) the phenotypic descriptor, preferably a recognizably distinct phenotype. We assert that only by a combinatorial or dyadic approach taking both of these attributes into account can a unitary, distinct genetic disorder be designated. We propose that all Mendelian disorders should be designated as "GENE-related phenotype descriptor" (e.g., "CFTR-related cystic fibrosis"). This approach to delineating and naming disorders reconciles the complexity of gene-to-phenotype relationships in a simple and clear manner yet communicates the complexity and nuance of these relationships.Item Expanding the clinical phenotype of individuals with a 3-bp in-frame deletion of the NF1 gene (c.2970_2972del): an update of genotype-phenotype correlation(Springer Nature, 2019-04) Koczkowska, Magdalena; Callens, Tom; Gomes, Alicia; Sharp, Angela; Chen, Yunjia; Hicks, Alesha D.; Aylsworth, Arthur S.; Azizi, Amedeo A.; Basel, Donald G.; Bellus, Gary; Bird, Lynne M.; Blazo, Maria A.; Burke, Leah W.; Cannon, Ashley; Collins, Felicity; DeFilippo, Colette; Denayer, Ellen; Digilio, Maria C.; Dills, Shelley K.; Dosa, Laura; Greenwood, Robert S.; Griffis, Cristin; Gupta, Punita; Hachen, Rachel K.; Hernández-Chico, Concepción; Janssens, Sandra; Jones, Kristi J.; Jordan, Justin T.; Kannu, Peter; Korf, Bruce R.; Lewis, Andrea M.; Listernick, Robert H.; Lonardo, Fortunato; Mahoney, Maurice J.; Ojeda, Mayra Martinez; McDonald, Marie T.; McDougall, Carey; Mendelsohn, Nancy; Miller, David T.; Mori, Mari; Oostenbrink, Rianne; Perreault, Sebastién; Pierpont, Mary Ella; Piscopo, Carmelo; Pond, Dinel A.; Randolph, Linda M.; Rauen, Katherine A.; Rednam, Surya; Rutledge, S. Lane; Saletti, Veronica; Schaefer, G. Bradley; Schorry, Elizabeth K.; Scott, Daryl A.; Shugar, Andrea; Siqveland, Elizabeth; Starr, Lois J.; Syed, Ashraf; Trapane, Pamela L.; Ullrich, Nicole J.; Wakefield, Emily G.; Walsh, Laurence E.; Wangler, Michael F.; Zackai, Elaine; Claes, Kathleen B. M.; Wimmer, Katharina; van Minkelen, Rick; De Luca, Alessandro; Martin, Yolanda; Legius, Eric; Messiaen, Ludwine M.; Neurology, School of MedicinePURPOSE: Neurofibromatosis type 1 (NF1) is characterized by a highly variable clinical presentation, but almost all NF1-affected adults present with cutaneous and/or subcutaneous neurofibromas. Exceptions are individuals heterozygous for the NF1 in-frame deletion, c.2970_2972del (p.Met992del), associated with a mild phenotype without any externally visible tumors. METHODS: A total of 135 individuals from 103 unrelated families, all carrying the constitutional NF1 p.Met992del pathogenic variant and clinically assessed using the same standardized phenotypic checklist form, were included in this study. RESULTS: None of the individuals had externally visible plexiform or histopathologically confirmed cutaneous or subcutaneous neurofibromas. We did not identify any complications, such as symptomatic optic pathway gliomas (OPGs) or symptomatic spinal neurofibromas; however, 4.8% of individuals had nonoptic brain tumors, mostly low-grade and asymptomatic, and 38.8% had cognitive impairment/learning disabilities. In an individual with the NF1 constitutional c.2970_2972del and three astrocytomas, we provided proof that all were NF1-associated tumors given loss of heterozygosity at three intragenic NF1 microsatellite markers and c.2970_2972del. CONCLUSION: We demonstrate that individuals with the NF1 p.Met992del pathogenic variant have a mild NF1 phenotype lacking clinically suspected plexiform, cutaneous, or subcutaneous neurofibromas. However, learning difficulties are clearly part of the phenotypic presentation in these individuals and will require specialized care.Item Functional and clinical studies reveal pathophysiological complexity of CLCN4-related neurodevelopmental condition(Springer Nature, 2023) Palmer, Elizabeth E.; Pusch, Michael; Picollo, Alessandra; Forwood, Caitlin; Nguyen, Matthew H.; Suckow, Vanessa; Gibbons, Jessica; Hoff, Alva; Sigfrid, Lisa; Megarbane, Andre; Nizon, Mathilde; Cogné, Benjamin; Beneteau, Claire; Alkuraya, Fowzan S.; Chedrawi, Aziza; Hashem, Mais O.; Stamberger, Hannah; Weckhuysen, Sarah; Vanlander, Arnaud; Ceulemans, Berten; Rajagopalan, Sulekha; Nunn, Kenneth; Arpin, Stéphanie; Raynaud, Martine; Motter, Constance S.; Ward-Melver, Catherine; Janssens, Katrien; Meuwissen, Marije; Beysen, Diane; Dikow, Nicola; Grimmel, Mona; Haack, Tobias B.; Clement, Emma; McTague, Amy; Hunt, David; Townshend, Sharron; Ward, Michelle; Richards, Linda J.; Simons, Cas; Costain, Gregory; Dupuis, Lucie; Mendoza-Londono, Roberto; Dudding-Byth, Tracy; Boyle, Jackie; Saunders, Carol; Fleming, Emily; El Chehadeh, Salima; Spitz, Marie-Aude; Piton, Amelie; Gerard, Bénédicte; Warde, Marie-Thérèse Abi; Rea, Gillian; McKenna, Caoimhe; Douzgou, Sofia; Banka, Siddharth; Akman, Cigdem; Bain, Jennifer M.; Sands, Tristan T.; Wilson, Golder N.; Silvertooth, Erin J.; Miller, Lauren; Lederer, Damien; Sachdev, Rani; Macintosh, Rebecca; Monestier, Olivier; Karadurmus, Deniz; Collins, Felicity; Carter, Melissa; Rohena, Luis; Willemsen, Marjolein H.; Ockeloen, Charlotte W.; Pfundt, Rolph; Kroft, Sanne D.; Field, Michael; Laranjeira, Francisco E. R.; Fortuna, Ana M.; Soares, Ana R.; Michaud, Vincent; Naudion, Sophie; Golla, Sailaja; Weaver, David D.; Bird, Lynne M.; Friedman, Jennifer; Clowes, Virginia; Joss, Shelagh; Pölsler, Laura; Campeau, Philippe M.; Blazo, Maria; Bijlsma, Emilia K.; Rosenfeld, Jill A.; Beetz, Christian; Powis, Zöe; McWalter, Kirsty; Brandt, Tracy; Torti, Erin; Mathot, Mikaël; Mohammad, Shekeeb S.; Armstrong, Ruth; Kalscheuer, Vera M.; Medical and Molecular Genetics, School of MedicineMissense and truncating variants in the X-chromosome-linked CLCN4 gene, resulting in reduced or complete loss-of-function (LOF) of the encoded chloride/proton exchanger ClC-4, were recently demonstrated to cause a neurocognitive phenotype in both males and females. Through international clinical matchmaking and interrogation of public variant databases we assembled a database of 90 rare CLCN4 missense variants in 90 families: 41 unique and 18 recurrent variants in 49 families. For 43 families, including 22 males and 33 females, we collated detailed clinical and segregation data. To confirm causality of variants and to obtain insight into disease mechanisms, we investigated the effect on electrophysiological properties of 59 of the variants in Xenopus oocytes using extended voltage and pH ranges. Detailed analyses revealed new pathophysiological mechanisms: 25% (15/59) of variants demonstrated LOF, characterized by a "shift" of the voltage-dependent activation to more positive voltages, and nine variants resulted in a toxic gain-of-function, associated with a disrupted gate allowing inward transport at negative voltages. Functional results were not always in line with in silico pathogenicity scores, highlighting the complexity of pathogenicity assessment for accurate genetic counselling. The complex neurocognitive and psychiatric manifestations of this condition, and hitherto under-recognized impacts on growth, gastrointestinal function, and motor control are discussed. Including published cases, we summarize features in 122 individuals from 67 families with CLCN4-related neurodevelopmental condition and suggest future research directions with the aim of improving the integrated care for individuals with this diagnosis.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 Rare deleterious mutations of HNRNP genes result in shared neurodevelopmental disorders(BMC, 2021-04-19) Gillentine, Madelyn A.; Wang, Tianyun; Hoekzema, Kendra; Rosenfeld, Jill; Liu, Pengfei; Guo, Hui; Kim, Chang N.; De Vries, Bert B.A.; Vissers, Lisenka E.L.M.; Nordenskjold, Magnus; Kvarnung, Malin; Lindstrand, Anna; Nordgren, Ann; Gecz, Jozef; Iascone, Maria; Cereda, Anna; Scatigno, Agnese; Maitz, Silvia; Zanni, Ginevra; Bertini, Enrico; Zweier, Christiane; Schuhmann, Sarah; Wiesener, Antje; Pepper, Micah; Panjwani, Heena; Torti, Erin; Abid, Farida; Anselm, Irina; Srivastava, Siddharth; Atwal, Paldeep; Bacino, Carlos A.; Bhat, Gifty; Cobian, Katherine; Bird, Lynne M.; Friedman, Jennifer; Wright, Meredith S.; Callewaert, Bert; Petit, Florence; Mathieu, Sophie; Afenjar, Alexandra; Christensen, Celenie K.; White, Kerry M.; Elpeleg, Orly; Berger, Itai; Espineli, Edward J.; Fagerberg, Christina; Brasch-Andersen, Charlotte; Hansen, Lars Kjærsgaard; Feyma, Timothy; Hughes, Susan; Thiffault, Isabelle; Sullivan, Bonnie; Yan, Shuang; Keller, Kory; Keren, Boris; Mignot, Cyril; Kooy, Frank; Meuwissen, Marije; Basinger, Alice; Kukolich, Mary; Philips, Meredith; Ortega, Lucia; Drummond-Borg, Margaret; Lauridsen, Mathilde; Sorensen, Kristina; Lehman, Anna; Lopez-Range, Elena; Levy, Paul; Lessel, Davor; Lotze, Timothy; Madan-Khetarpal, Suneeta; Sebastian, Jessica; Vento, Jodie; Vats, Divya; Benman, L. Manace; Mckee, Shane; Mirzaa, Ghayda M.; Muss, Candace; Pappas, John; Peeters, Hilde; Romano, Corrado; Elia, Maurizio; Galesi, Ornella; Simon, Marleen E.H.; Van Gassen, Koen L.I.; Simpson, Kara; Stratton, Robert; Syed, Sabeen; Thevenon, Julien; Palafoll, Irene Valenzuela; Vitobello, Antonio; Bournez, Marie; Faivre, Laurence; Xia, Kun; Earl, Rachel K.; Nowakowski, Tomasz; Bernier, Raphael A.; Eichler, Evan E.; Pediatrics, School of MedicineBackground: With the increasing number of genomic sequencing studies, hundreds of genes have been implicated in neurodevelopmental disorders (NDDs). The rate of gene discovery far outpaces our understanding of genotype-phenotype correlations, with clinical characterization remaining a bottleneck for understanding NDDs. Most disease-associated Mendelian genes are members of gene families, and we hypothesize that those with related molecular function share clinical presentations. Methods: We tested our hypothesis by considering gene families that have multiple members with an enrichment of de novo variants among NDDs, as determined by previous meta-analyses. One of these gene families is the heterogeneous nuclear ribonucleoproteins (hnRNPs), which has 33 members, five of which have been recently identified as NDD genes (HNRNPK, HNRNPU, HNRNPH1, HNRNPH2, and HNRNPR) and two of which have significant enrichment in our previous meta-analysis of probands with NDDs (HNRNPU and SYNCRIP). Utilizing protein homology, mutation analyses, gene expression analyses, and phenotypic characterization, we provide evidence for variation in 12 HNRNP genes as candidates for NDDs. Seven are potentially novel while the remaining genes in the family likely do not significantly contribute to NDD risk. Results: We report 119 new NDD cases (64 de novo variants) through sequencing and international collaborations and combined with published clinical case reports. We consider 235 cases with gene-disruptive single-nucleotide variants or indels and 15 cases with small copy number variants. Three hnRNP-encoding genes reach nominal or exome-wide significance for de novo variant enrichment, while nine are candidates for pathogenic mutations. Comparison of HNRNP gene expression shows a pattern consistent with a role in cerebral cortical development with enriched expression among radial glial progenitors. Clinical assessment of probands (n = 188-221) expands the phenotypes associated with HNRNP rare variants, and phenotypes associated with variation in the HNRNP genes distinguishes them as a subgroup of NDDs. Conclusions: Overall, our novel approach of exploiting gene families in NDDs identifies new HNRNP-related disorders, expands the phenotypes of known HNRNP-related disorders, strongly implicates disruption of the hnRNPs as a whole in NDDs, and supports that NDD subtypes likely have shared molecular pathogenesis. To date, this is the first study to identify novel genetic disorders based on the presence of disorders in related genes. We also perform the first phenotypic analyses focusing on related genes. Finally, we show that radial glial expression of these genes is likely critical during neurodevelopment. This is important for diagnostics, as well as developing strategies to best study these genes for the development of therapeutics.Item Response to Hamosh et al(Elsevier, 2021) Biesecker, Leslie G.; Adam, Margaret P.; Alkuraya, Fowzan S.; Amemiya, Anne R.; Bamshad, Michael J.; Beck, Anita E.; Bennett, James T.; Bird, Lynne M.; Carey, John C.; Chung, Brian; Clark, Robin D.; Cox, Timothy C.; Curry, Cynthia; Dinulos, Mary Beth Palko; Dobyns, William B.; Giampietro, Philip F.; Girisha, Katta M.; Glass, Ian A.; Graham, John M., Jr.; Gripp, Karen W.; Haldeman-Englert, Chad R.; Hall, Bryan D.; Innes, A. Micheil; Kalish, Jennifer M.; Keppler-Noreuil, Kim M.; Kosaki, Kenjiro; Kozel, Beth A.; Mirzaa, Ghayda M.; Mulvihill, John J.; Nowaczyk, Malgorzata J.M.; Pagon, Roberta A.; Retterer, Kyle; Rope, Alan F.; Sanchez-Lara, Pedro A.; Seaver, Laurie H.; Shieh, Joseph T.; Slavotinek, Anne M.; Sobering, Andrew K.; Stevens, Cathy A.; Stevenson, David A.; Tan, Tiong Yang; Tan, Wen-Hann; Tsai, Anne C.; Weaver, David D.; Williams, Marc S.; Zackai, Elaine; Zarate, Yuri A.; Medical and Molecular Genetics, School of MedicineItem WDR26 Haploinsufficiency Causes a Recognizable Syndrome of Intellectual Disability, Seizures, Abnormal Gait, and Distinctive Facial Features(Elsevier, 2017-07-06) Skraban, Cara M.; Wells, Constance F.; Markose, Preetha; Cho, Megan T.; Nesbitt, Addie I.; Au, P.Y. Billie; Begtrup, Amber; Bernat, John A.; Bird, Lynne M.; Cao, Kajia; de Brouwer, Arjan P.M.; Denenberg, Elizabeth H.; Douglas, Ganka; Gibson, Kristin M.; Grand, Katheryn; Goldenberg, Alice; Innes, A. Micheil; Juusola, Jane; Kempers, Marlies; Kinning, Esther; Markie, David M.; Owens, Martina M.; Payne, Katelyn; Person, Richard; Pfundt, Rolph; Stocco, Amber; Turner, Claire L.S.; Verbeek, Nienke E.; Walsh, Laurence E.; Warner, Taylor C.; Wheeler, Patricia G.; Wieczorek, Dagmar; Wilkens, Alisha B.; Zonneveld-Huijssoon, Evelien; Deciphering Developmental Disorders Study; Kleefstra, Tjitske; Robertson, Stephen P.; Santani, Avni; van Gassen, Koen L.I.; Deardorf, Matthew A.; Pediatrics, School of MedicineWe report 15 individuals with de novo pathogenic variants in WDR26. Eleven of the individuals carry loss-of-function mutations, and four harbor missense substitutions. These 15 individuals comprise ten females and five males, and all have intellectual disability with delayed speech, a history of febrile and/or non-febrile seizures, and a wide-based, spastic, and/or stiff-legged gait. These subjects share a set of common facial features that include a prominent maxilla and upper lip that readily reveal the upper gingiva, widely spaced teeth, and a broad nasal tip. Together, these features comprise a recognizable facial phenotype. We compared these features with those of chromosome 1q41q42 microdeletion syndrome, which typically contains WDR26, and noted that clinical features are consistent between the two subsets, suggesting that haploinsufficiency of WDR26 contributes to the pathology of 1q41q42 microdeletion syndrome. Consistent with this, WDR26 loss-of-function single-nucleotide mutations identified in these subjects lead to nonsense-mediated decay with subsequent reduction of RNA expression and protein levels. We derived a structural model of WDR26 and note that missense variants identified in these individuals localize to highly conserved residues of this WD-40-repeat-containing protein. Given that WDR26 mutations have been identified in ∼1 in 2,000 of subjects in our clinical cohorts and that WDR26 might be poorly annotated in exome variant-interpretation pipelines, we would anticipate that this disorder could be more common than currently appreciated.