Browsing by Author "Legius, Eric"

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    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 Medicine
    Purpose: 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.
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    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 Medicine
    PURPOSE: 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.
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    The path forward: 2015 International Children's Tumor Foundation conference on neurofibromatosis type 1, type 2, and schwannomatosis
    (Wiley, 2017-06) Blakely, Jaishri O.; Bakker, Annette; Barker, Anne; Clapp, Wade; Ferner, Rosalie; Fisher, Michael J.; Giovannini, Marco; Gutmann, David H.; Karajannis, Matthias A.; Kissil, Joseph L.; Legius, Eric; Lloyd, Alison C.; Packer, Roger J.; Ramesh, Vijaya; Riccardi, Vincent M.; Stevenson, David A.; Ullrich, Nicole J.; Upadhyaya, Meena; Stemmer-Rachamimov, Anat; Pediatrics, School of Medicine
    The Annual Children's Tumor Foundation International Neurofibromatosis Meeting is the premier venue for connecting discovery, translational and clinical scientists who are focused on neurofibromatosis types 1 and 2 (NF1 and NF2) and schwannomatosis (SWN). The meeting also features rare tumors such as glioma, meningioma, sarcoma, and neuroblastoma that occur both within these syndromes and spontaneously; associated with somatic mutations in NF1, NF2, and SWN. The meeting addresses both state of the field for current clinical care as well as emerging preclinical models fueling discovery of new therapeutic targets and discovery science initiatives investigating mechanisms of tumorigenesis. Importantly, this conference is a forum for presenting work in progress and bringing together all stakeholders in the scientific community. A highlight of the conference was the involvement of scientists from the pharmaceutical industry who presented growing efforts for rare disease therapeutic development in general and specifically, in pediatric patients with rare tumor syndromes. Another highlight was the focus on new investigators who presented new data about biomarker discovery, tumor pathogenesis, and diagnostic tools for NF1, NF2, and SWN. This report summarizes the themes of the meeting and a synthesis of the scientific discoveries presented at the conference in order to make the larger research community aware of progress in the neurofibromatoses.
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    TNPO2 variants associate with human developmental delays, neurologic deficits, and dysmorphic features and alter TNPO2 activity in Drosophila
    (Elsevier, 2021) Goodman, Lindsey D.; Cope, Heidi; Nil, Zelha; Ravenscroft, Thomas A.; Charng, Wu-Lin; Lu, Shenzhao; Tien, An-Chi; Pfundt, Rolph; Koolen, David A.; Haaxma, Charlotte A.; Veenstra-Knol, Hermine E.; Klein Wassink-Ruiter, Jolien S.; Wevers, Marijke R.; Jones, Melissa; Walsh, Laurence E.; Klee, Victoria H.; Theunis, Miel; Legius, Eric; Steel, Dora; Barwick, Katy E.S.; Kurian, Manju A.; Mohammad, Shekeeb. S.; Dale, Russell C.; Terhal, Paulien A.; van Binsbergen, Ellen; Kirmse, Brian; Robinette, Bethany; Cogné, Benjamin; Isidor, Bertrand; Grebe, Theresa A.; Kulch, Peggy; Hainline, Bryan E.; Sapp, Katherine; Morava, Eva; Klee, Eric W.; Macke, Erica L.; Trapane, Pamela; Spencer, Christopher; Si, Yue; Begtrup, Amber; Moulton, Matthew J.; Dutta, Debdeep; Kanca, Oguz; Undiagnosed Diseases Network; Wangler, Michael F.; Yamamoto, Shinya; Bellen, Hugo J.; Tan, Queenie K.G.; Pediatrics, School of Medicine
    Transportin-2 (TNPO2) mediates multiple pathways including non-classical nucleocytoplasmic shuttling of >60 cargoes, such as developmental and neuronal proteins. We identified 15 individuals carrying de novo coding variants in TNPO2 who presented with global developmental delay (GDD), dysmorphic features, ophthalmologic abnormalities, and neurological features. To assess the nature of these variants, functional studies were performed in Drosophila. We found that fly dTnpo (orthologous to TNPO2) is expressed in a subset of neurons. dTnpo is critical for neuronal maintenance and function as downregulating dTnpo in mature neurons using RNAi disrupts neuronal activity and survival. Altering the activity and expression of dTnpo using mutant alleles or RNAi causes developmental defects, including eye and wing deformities and lethality. These effects are dosage dependent as more severe phenotypes are associated with stronger dTnpo loss. Interestingly, similar phenotypes are observed with dTnpo upregulation and ectopic expression of TNPO2, showing that loss and gain of Transportin activity causes developmental defects. Further, proband-associated variants can cause more or less severe developmental abnormalities compared to wild-type TNPO2 when ectopically expressed. The impact of the variants tested seems to correlate with their position within the protein. Specifically, those that fall within the RAN binding domain cause more severe toxicity and those in the acidic loop are less toxic. Variants within the cargo binding domain show tissue-dependent effects. In summary, dTnpo is an essential gene in flies during development and in neurons. Further, proband-associated de novo variants within TNPO2 disrupt the function of the encoded protein. Hence, TNPO2 variants are causative for neurodevelopmental abnormalities.