Title: | De Novo and Inherited Loss-of-Function Variants in TLK2: Clinical and Genotype-Phenotype Evaluation of a Distinct Neurodevelopmental Disorder |
Author(s): | Reijnders, M.R.F. ; Miller, K.A.; Alvi, M.; Goos, J.A.C.; Lees, M.M.; Burca, A. de; Henderson, A.; Kraus, A.; Mikat, B.; Vries, B.B.A. de ; Isidor, B.; Kerr, B.; Marcelis, C.L.M. ; Schluth-Bolard, C.; Deshpande, C.; Ruivenkamp, C.A.L.; Wieczorek, D.; Baralle, D.; Blair, E.M.; Engels, H.; Ludecke, H.J.; Eason, J.; Santen, G.W.E.; Clayton-Smith, J.; Chandler, K.; Tatton-Brown, K.; Payne, K.; Helbig, K.; Radtke, K.; Nugent, K.M.; Cremer, K.; Strom, T.M.; Bird, L.M.; Sinnema, M.; Bitner-Glindzicz, M.; Dooren, M.F. van; Alders, M.; Koopmans, M.; Brick, L.; Kozenko, M.; Harline, M.L.; Klaassens, M.; Steinraths, M.; Cooper, N.S.; Edery, P.; Yap, P.; Terhal, P.A.; Spek, P.J. van der; Lakeman, P.; Taylor, R.L.; Littlejohn, R.O.; Pfundt, R.P. ; Mercimek-Andrews, S.; Stegmann, A.P.A.; Kant, S.G.; McLean, S.; Joss, S.; Swagemakers, S.M.A.; Douzgou, S.; Wall, S.A.; Kury, S.; Calpena, E.; Koelling, N.; McGowan, S.J.; Twigg, S.R.F.; Mathijssen, I.M.J.; Nellaker, C.; Brunner, H.G. ; Wilkie, A.O.M. |
Publication year: | 2018 |
Source: | American Journal of Human Genetics, vol. 102, iss. 6, (2018), pp. 1195-1203 |
ISSN: | 0002-9297 |
DOI: | https://doi.org/10.1016/j.ajhg.2018.04.014 |
Publication type: | Article / Letter to editor |
Please use this identifier to cite or link to this item : https://hdl.handle.net/2066/193340 ![]() |
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Subject: | Radboudumc 7: Neurodevelopmental disorders DCMN: Donders Center for Medical Neuroscience Radboudumc 9: Rare cancers RIHS: Radboud Institute for Health Sciences Tijdelijke code tbv inlezen publicaties Radboudumc - Alleen voor gebruik door Radboudumc |
Organization: | Human Genetics |
Journal title: |
American Journal of Human Genetics
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Volume: | vol. 102 |
Issue: | iss. 6 |
Page start: | p. 1195 |
Page end: | p. 1203 |
Abstract: |
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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