Browsing by Author "Wieczorek, Dagmar"

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    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 Medicine
    Next-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.
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    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 Medicine
    We 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.