Browsing by Author "Haack, Tobias B."

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    DNA-binding affinity and specificity determine the phenotypic diversity in BCL11B-related disorders
    (Elsevier, 2025) Lessel, Ivana; Baresic, Anja; Chinn, Ivan K.; May, Jonathan; Goenka, Anu; Chandler, Kate E.; Posey, Jennifer E.; Afenjar, Alexandra; Averdunk, Luisa; Bedeschi, Maria Francesca; Besnard, Thomas; Brager, Rae; Brick, Lauren; Brugger, Melanie; Brunet, Theresa; Byrne, Susan; de la Calle-Martín, Oscar; Capra, Valeria; Cardenas, Paul; Chappé, Céline; Chong, Hey J.; Cogne, Benjamin; Conboy, Erin; Cope, Heidi; Courtin, Thomas; Deb, Wallid; Dilena, Robertino; Dubourg, Christèle; Elgizouli, Magdeldin; Fernandes, Erica; Fitzgerald, Kristi K.; Gangi, Silvana; George-Abraham, Jaya K.; Gucsavas-Calikoglu, Muge; Haack, Tobias B.; Hadonou, Medard; Hanker, Britta; Hüning, Irina; Iascone, Maria; Isidor, Bertrand; Järvelä, Irma; Jin, Jay J.; Jorge, Alexander A. L.; Josifova, Dragana; Kalinauskiene, Ruta; Kamsteeg, Erik-Jan; Keren, Boris; Kessler, Elena; Kölbel, Heike; Kozenko, Mariya; Kubisch, Christian; Kuechler, Alma; Leal, Suzanne M.; Leppälä, Juha; Luu, Sharon M.; Lyon, Gholson J.; Madan-Khetarpal, Suneeta; Mancardi, Margherita; Marchi, Elaine; Mehta, Lakshmi; Menendez, Beatriz; Morel, Chantal F.; Moyer Harasink, Sue; Nevay, Dayna-Lynn; Nigro, Vincenzo; Odent, Sylvie; Oegema, Renske; Pappas, John; Pastore, Matthew T.; Perilla-Young, Yezmin; Platzer, Konrad; Powell-Hamilton, Nina; Rabin, Rachel; Rekab, Aisha; Rezende, Raissa C.; Robert, Leema; Romano, Ferruccio; Scala, Marcello; Poths, Karin; Schrauwen, Isabelle; Sebastian, Jessica; Short, John; Sidlow, Richard; Sullivan, Jennifer; Szakszon, Katalin; Tan, Queenie K. G.; Undiagnosed Diseases Network; Wagner, Matias; Wieczorek, Dagmar; Yuan, Bo; Maeding, Nicole; Strunk, Dirk; Begtrup, Amber; Banka, Siddharth; Lupski, James R.; Tolosa, Eva; Lessel, Davor; Medical and Molecular Genetics, School of Medicine
    BCL11B is a Cys2-His2 zinc-finger (C2H2-ZnF) domain-containing, DNA-binding, transcription factor with established roles in the development of various organs and tissues, primarily the immune and nervous systems. BCL11B germline variants have been associated with a variety of developmental syndromes. However, genotype-phenotype correlations along with pathophysiologic mechanisms of selected variants mostly remain elusive. To dissect these, we performed genotype-phenotype correlations of 92 affected individuals harboring a pathogenic or likely pathogenic BCL11B variant, followed by immune phenotyping, analysis of chromatin immunoprecipitation DNA-sequencing data, dual-luciferase reporter assays, and molecular modeling. These integrative analyses enabled us to define three clinical subtypes of BCL11B-related disorders. It is likely that gene-disruptive BCL11B variants and missense variants affecting zinc-binding cysteine and histidine residues cause mild to moderate neurodevelopmental delay with increased propensity for behavioral and dental anomalies, allergies and asthma, and reduced type 2 innate lymphoid cells. Missense variants within C2H2-ZnF DNA-contacting α helices cause highly variable clinical presentations ranging from multisystem anomalies with demise in the first years of life to late-onset, hyperkinetic movement disorder with poor fine motor skills. Those not in direct DNA contact cause a milder phenotype through reduced, target-specific transcriptional activity. However, missense variants affecting C2H2-ZnFs, DNA binding, and "specificity residues" impair BCL11B transcriptional activity in a target-specific, dominant-negative manner along with aberrant regulation of alternative DNA targets, resulting in more severe and unpredictable clinical outcomes. Taken together, we suggest that the phenotypic severity and variability is largely dependent on the DNA-binding affinity and specificity of altered BCL11B proteins.
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    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 Medicine
    Missense 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.
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    Heterozygous loss-of-function SMC3 variants are associated with variable and incompletely penetrant growth and developmental features
    (medRxiv, 2023-09-28) Ansari, Morad; Faour, Kamli N. W.; Shimamura, Akiko; Grimes, Graeme; Kao, Emeline M.; Denhoff, Erica R.; Blatnik, Ana; Ben-Isvy, Daniel; Wang, Lily; Helm, Benjamin M.; Firth, Helen; Breman, Amy M.; Bijlsma, Emilia K.; Iwata-Otsubo, Aiko; de Ravel, Thomy J. L.; Fusaro, Vincent; Fryer, Alan; Nykamp, Keith; Stühn, Lara G.; Haack, Tobias B.; Korenke, G. Christoph; Constantinou, Panayiotis; Bujakowska, Kinga M.; Low, Karen J.; Place, Emily; Humberson, Jennifer; Napier, Melanie P.; Hoffman, Jessica; Juusola, Jane; Deardorff, Matthew A.; Shao, Wanqing; Rockowitz, Shira; Krantz, Ian; Kaur, Maninder; Raible, Sarah; Kliesch, Sabine; Singer-Berk, Moriel; Groopman, Emily; DiTroia, Stephanie; Ballal, Sonia; Srivastava, Siddharth; Rothfelder, Kathrin; Biskup, Saskia; Rzasa, Jessica; Kerkhof, Jennifer; McConkey, Haley; O'Donnell-Luria, Anne; Sadikovic, Bekim; Hilton, Sarah; Banka, Siddharth; Tüttelmann, Frank; Conrad, Donald; Talkowski, Michael E.; FitzPatrick, David R.; Boone, Philip M.; Medical and Molecular Genetics, School of Medicine
    Heterozygous missense variants and in-frame indels in SMC3 are a cause of Cornelia de Lange syndrome (CdLS), marked by intellectual disability, growth deficiency, and dysmorphism, via an apparent dominant-negative mechanism. However, the spectrum of manifestations associated with SMC3 loss-of-function variants has not been reported, leading to hypotheses of alternative phenotypes or even developmental lethality. We used matchmaking servers, patient registries, and other resources to identify individuals with heterozygous, predicted loss-of-function (pLoF) variants in SMC3, and analyzed population databases to characterize mutational intolerance in this gene. Here, we show that SMC3 behaves as an archetypal haploinsufficient gene: it is highly constrained against pLoF variants, strongly depleted for missense variants, and pLoF variants are associated with a range of developmental phenotypes. Among 13 individuals with SMC3 pLoF variants, phenotypes were variable but coalesced on low growth parameters, developmental delay/intellectual disability, and dysmorphism reminiscent of atypical CdLS. Comparisons to individuals with SMC3 missense/in-frame indel variants demonstrated a milder presentation in pLoF carriers. Furthermore, several individuals harboring pLoF variants in SMC3 were nonpenetrant for growth, developmental, and/or dysmorphic features, some instead having intriguing symptomatologies with rational biological links to SMC3 including bone marrow failure, acute myeloid leukemia, and Coats retinal vasculopathy. Analyses of transcriptomic and epigenetic data suggest that SMC3 pLoF variants reduce SMC3 expression but do not result in a blood DNA methylation signature clustering with that of CdLS, and that the global transcriptional signature of SMC3 loss is model-dependent. Our finding of substantial population-scale LoF intolerance in concert with variable penetrance in subjects with SMC3 pLoF variants expands the scope of cohesinopathies, informs on their allelic architecture, and suggests the existence of additional clearly LoF-constrained genes whose disease links will be confirmed only by multi-layered genomic data paired with careful phenotyping.
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    Heterozygous loss-of-function SMC3 variants are associated with variable growth and developmental features
    (Elsevier, 2024) Ansari, Morad; Faour, Kamli N. W.; Shimamura, Akiko; Grimes, Graeme; Kao, Emeline M.; Denhoff, Erica R.; Blatnik, Ana; Ben-Isvy, Daniel; Wang, Lily; Helm, Benjamin M.; Firth, Helen; Breman, Amy M.; Bijlsma, Emilia K.; Iwata-Otsubo, Aiko; de Ravel, Thomy J. L.; Fusaro, Vincent; Fryer, Alan; Nykamp, Keith; Stühn, Lara G.; Haack, Tobias B.; Korenke, G. Christoph; Constantinou, Panayiotis; Bujakowska, Kinga M.; Low, Karen J.; Place, Emily; Humberson, Jennifer; Napier, Melanie P.; Hoffman, Jessica; Juusola, Jane; Deardorff, Matthew A.; Shao, Wanqing; Rockowitz, Shira; Krantz, Ian; Kaur, Maninder; Raible, Sarah; Dortenzio, Victoria; Kliesch, Sabine; Singer-Berk, Moriel; Groopman, Emily; DiTroia, Stephanie; Ballal, Sonia; Srivastava, Siddharth; Rothfelder, Kathrin; Biskup, Saskia; Rzasa, Jessica; Kerkhof, Jennifer; McConkey, Haley; Sadikovic, Bekim; Hilton, Sarah; Banka, Siddharth; Tüttelmann, Frank; Conrad, Donald F.; O'Donnell-Luria, Anne; Talkowski, Michael E.; FitzPatrick, David R.; Boone, Philip M.; Medical and Molecular Genetics, School of Medicine
    Heterozygous missense variants and in-frame indels in SMC3 are a cause of Cornelia de Lange syndrome (CdLS), marked by intellectual disability, growth deficiency, and dysmorphism, via an apparent dominant-negative mechanism. However, the spectrum of manifestations associated with SMC3 loss-of-function variants has not been reported, leading to hypotheses of alternative phenotypes or even developmental lethality. We used matchmaking servers, patient registries, and other resources to identify individuals with heterozygous, predicted loss-of-function (pLoF) variants in SMC3, and analyzed population databases to characterize mutational intolerance in this gene. Here, we show that SMC3 behaves as an archetypal haploinsufficient gene: it is highly constrained against pLoF variants, strongly depleted for missense variants, and pLoF variants are associated with a range of developmental phenotypes. Among 14 individuals with SMC3 pLoF variants, phenotypes were variable but coalesced on low growth parameters, developmental delay/intellectual disability, and dysmorphism, reminiscent of atypical CdLS. Comparisons to individuals with SMC3 missense/in-frame indel variants demonstrated an overall milder presentation in pLoF carriers. Furthermore, several individuals harboring pLoF variants in SMC3 were nonpenetrant for growth, developmental, and/or dysmorphic features, and some had alternative symptomatologies with rational biological links to SMC3. Analyses of tumor and model system transcriptomic data and epigenetic data in a subset of cases suggest that SMC3 pLoF variants reduce SMC3 expression but do not strongly support clustering with functional genomic signatures of typical CdLS. Our finding of substantial population-scale LoF intolerance in concert with variable growth and developmental features in subjects with SMC3 pLoF variants expands the scope of cohesinopathies, informs on their allelic architecture, and suggests the existence of additional clearly LoF-constrained genes whose disease links will be confirmed only by multilayered genomic data paired with careful phenotyping.
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    HNRNPC haploinsufficiency affects alternative splicing of intellectual disability-associated genes and causes a neurodevelopmental disorder
    (Elsevier, 2023) Niggl, Eva; Bouman, Arjan; Briere, Lauren C.; Hoogenboezem, Remco M.; Wallaard, Ilse; Park, Joohyun; Admard, Jakob; Wilke, Martina; Harris-Mostert, Emilio D. R. O.; Elgersma, Minetta; Bain, Jennifer; Balasubramanian, Meena; Banka, Siddharth; Benke, Paul J.; Bertrand, Miriam; Blesson, Alyssa E.; Clayton-Smith, Jill; Ellingford, Jamie M.; Gillentine, Madelyn A.; Goodloe, Dana H.; Haack, Tobias B.; Jain, Mahim; Krantz, Ian; Luu, Sharon M.; McPheron, Molly; Muss, Candace L.; Raible, Sarah E.; Robin, Nathaniel H.; Spiller, Michael; Starling, Susan; Sweetser, David A.; Thiffault, Isabelle; Vetrini, Francesco; Witt, Dennis; Woods, Emily; Zhou, Dihong; Genomics England Research Consortium; Undiagnosed Diseases Network; Elgersma, Ype; van Esbroeck, Annelot C. M.; Medical and Molecular Genetics, School of Medicine
    Heterogeneous nuclear ribonucleoprotein C (HNRNPC) is an essential, ubiquitously abundant protein involved in mRNA processing. Genetic variants in other members of the HNRNP family have been associated with neurodevelopmental disorders. Here, we describe 13 individuals with global developmental delay, intellectual disability, behavioral abnormalities, and subtle facial dysmorphology with heterozygous HNRNPC germline variants. Five of them bear an identical in-frame deletion of nine amino acids in the extreme C terminus. To study the effect of this recurrent variant as well as HNRNPC haploinsufficiency, we used induced pluripotent stem cells (iPSCs) and fibroblasts obtained from affected individuals. While protein localization and oligomerization were unaffected by the recurrent C-terminal deletion variant, total HNRNPC levels were decreased. Previously, reduced HNRNPC levels have been associated with changes in alternative splicing. Therefore, we performed a meta-analysis on published RNA-seq datasets of three different cell lines to identify a ubiquitous HNRNPC-dependent signature of alternative spliced exons. The identified signature was not only confirmed in fibroblasts obtained from an affected individual but also showed a significant enrichment for genes associated with intellectual disability. Hence, we assessed the effect of decreased and increased levels of HNRNPC on neuronal arborization and neuronal migration and found that either condition affects neuronal function. Taken together, our data indicate that HNRNPC haploinsufficiency affects alternative splicing of multiple intellectual disability-associated genes and that the developing brain is sensitive to aberrant levels of HNRNPC. Hence, our data strongly support the inclusion of HNRNPC to the family of HNRNP-related neurodevelopmental disorders.