Browsing by Author "Lessel, Davor"

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    The analysis of heterotaxy patients reveals new loss-of-function variants of GRK5
    (SpringerNature, 2016-09-13) Lessel, Davor; Muhammad, Tariq; Tena, Teresa Casar; Moepps, Barbara; Burkhalter, Martin D.; Hitz, Marc-Phillip; Toka, Okan; Rentzsch, Axel; Schubert, Stephan; Schalinski, Adelheid; Bauer, Ulrike M. M.; Kubisch, Christian; Ware, Stephanie M.; Philipp, Melanie; Department of Pediatrics, IU School of Medicine
    G protein-coupled receptor kinase 5 (GRK5) is a regulator of cardiac performance and a potential therapeutic target in heart failure in the adult. Additionally, we have previously classified GRK5 as a determinant of left-right asymmetry and proper heart development using zebrafish. We thus aimed to identify GRK5 variants of functional significance by analysing 187 individuals with laterality defects (heterotaxy) that were associated with a congenital heart defect (CHD). Using Sanger sequencing we identified two moderately frequent variants in GRK5 with minor allele frequencies <10%, and seven very rare polymorphisms with minor allele frequencies <1%, two of which are novel variants. Given their evolutionarily conserved position in zebrafish, in-depth functional characterisation of four variants (p.Q41L, p.G298S, p.R304C and p.T425M) was performed. We tested the effects of these variants on normal subcellular localisation and the ability to desensitise receptor signalling as well as their ability to correct the left-right asymmetry defect upon Grk5l knockdown in zebrafish. While p.Q41L, p.R304C and p.T425M responded normally in the first two aspects, neither p.Q41L nor p.R304C were capable of rescuing the lateralisation phenotype. The fourth variant, p.G298S was identified as a complete loss-of-function variant in all assays and provides insight into the functions of GRK5.
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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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    Lessons learned from additional research analyses of unsolved clinical exome cases
    (BioMed Central, 2017-03-21) Eldomery, Mohammad K.; Coban-Akdemir, Zeynep; Harel, Tamar; Rosenfeld, Jill A.; Gambin, Tomasz; Stray-Pedersen, Asbjørg; Küry, Sébastien; Mercier, Sandra; Lessel, Davor; Denecke, Jonas; Wiszniewski, Wojciech; Penney, Samantha; Liu, Pengfei; Bi, Weimin; Lalani, Seema R.; Schaaf, Christian P.; Wangler, Michael F.; Bacino, Carlos A.; Lewis, Richard Alan; Potocki, Lorraine; Graham, Brett H.; Belmont, John W.; Scaglia, Fernando; Orange, Jordan S.; Jhangiani, Shalini N.; Chiang, Theodore; Doddapaneni, Harsha; Hu, Jianhong; Muzny, Donna M.; Xia, Fan; Beaudet, Arthur L.; Boerwinkle, Eric; Eng, Christine M.; Plon, Sharon E.; Sutton, V. Reid; Gibbs, Richard A.; Posey, Jennifer E.; Yang, Yaping; Lupski, James R.; Department of Pathology and Laboratory Medicine, IU School of Medicine
    BACKGROUND: Given the rarity of most single-gene Mendelian disorders, concerted efforts of data exchange between clinical and scientific communities are critical to optimize molecular diagnosis and novel disease gene discovery. METHODS: We designed and implemented protocols for the study of cases for which a plausible molecular diagnosis was not achieved in a clinical genomics diagnostic laboratory (i.e. unsolved clinical exomes). Such cases were recruited to a research laboratory for further analyses, in order to potentially: (1) accelerate novel disease gene discovery; (2) increase the molecular diagnostic yield of whole exome sequencing (WES); and (3) gain insight into the genetic mechanisms of disease. Pilot project data included 74 families, consisting mostly of parent-offspring trios. Analyses performed on a research basis employed both WES from additional family members and complementary bioinformatics approaches and protocols. RESULTS: Analysis of all possible modes of Mendelian inheritance, focusing on both single nucleotide variants (SNV) and copy number variant (CNV) alleles, yielded a likely contributory variant in 36% (27/74) of cases. If one includes candidate genes with variants identified within a single family, a potential contributory variant was identified in a total of ~51% (38/74) of cases enrolled in this pilot study. The molecular diagnosis was achieved in 30/63 trios (47.6%). Besides this, the analysis workflow yielded evidence for pathogenic variants in disease-associated genes in 4/6 singleton cases (66.6%), 1/1 multiplex family involving three affected siblings, and 3/4 (75%) quartet families. Both the analytical pipeline and the collaborative efforts between the diagnostic and research laboratories provided insights that allowed recent disease gene discoveries (PURA, TANGO2, EMC1, GNB5, ATAD3A, and MIPEP) and increased the number of novel genes, defined in this study as genes identified in more than one family (DHX30 and EBF3). CONCLUSION: An efficient genomics pipeline in which clinical sequencing in a diagnostic laboratory is followed by the detailed reanalysis of unsolved cases in a research environment, supplemented with WES data from additional family members, and subject to adjuvant bioinformatics analyses including relaxed variant filtering parameters in informatics pipelines, can enhance the molecular diagnostic yield and provide mechanistic insights into Mendelian disorders. Implementing these approaches requires collaborative clinical molecular diagnostic and research efforts.
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    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 Medicine
    Background: 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.