Browsing by Author "Li, Yun"

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    A comprehensive molecular study on Coffin-Siris and Nicolaides-Baraitser syndromes identifies a broad molecular and clinical spectrum converging on altered chromatin remodeling
    (OXFORD UNIV PRESS, 2013-01-01) Wieczorek, Dagmar; Boegershausen, Nina; Beleggia, Filippo; Steiner-Haldenstaett, Sabine; Pohl, Esther; Li, Yun; Milz, Esther; Martin, Marcel; Thiele, Holger; Altmueller, Janine; Alanay, Yasemin; Kayserili, Hulya; Klein-Hitpass, Ludger; Bohringer, Stefan; Wollstein, Andreas; Albrecht, Beate; Boduroglu, Koray; Caliebe, Almuth; Chrzanowska, Krystyna; Cogulu, Ozgur; Cristofoli, Francesca; Czeschik, Johanna Christina; Devriendt, Koenraad; Dotti, Maria Teresa; Elcioglu, Nursel; Gener, Blanca; Goecke, Timm O.; Krajewska-Walasek, Malgorzata; Guillen-Navarro, Encarnacion; Hayek, Joussef; Houge, Gunnar; Kilic, Esra; Simsek-Kiper, Pelin Ozlem; Lopez-Gonzalez, Vanesa; Kuechler, Alma; Lyonnet, Stanislas; Mari, Francesca; Marozza, Annabella; Dramard, Michele Mathieu; Mikat, Barbara; Morin, Gilles; Morice-Picard, Fanny; Ozkinay, Ferda; Rauch, Anita; Renieri, Alessandra; Tinschert, Sigrid; Utine, G. Eda; Vilain, Catheline; Vivarelli, Rossella; Zweier, Christiane; Nuernberg, Peter; Rahmann, Sven; Vermeesch, Joris; Luedecke, Hermann-Josef; Zeschnigk, Michael; Wollnik, Bernd
    Chromatin remodeling complexes are known to modify chemical marks on histones or to induce conformational changes in the chromatin in order to regulate transcription. Denovodominant mutations in different members of the SWI/SNF chromatin remodeling complex have recently been described in individuals with Coffin-Siris (CSS) and Nicolaides-Baraitser (NCBRS) syndromes. Using a combination of whole-exome sequencing, NGS-based sequencing of 23 SWI/SNF complex genes, and molecular karyotyping in 46 previously undescribed individuals with CSS and NCBRS, we identified a de novo 1-bp deletion (c.677delG, p.Gly226Glufs{*}53) and a de novo missense mutation (c.914G>T, p.Cys305Phe) in PHF6 in two individuals diagnosed with CSS. PHF6 interacts with the nucleosome remodeling and deacetylation ( NuRD) complex implicating dysfunction of a second chromatin remodeling complex in the pathogenesis of CSS-like phenotypes. Altogether, we identified mutations in 60\% of the studied individuals (28/46), located in the genes ARID1A, ARID1B, SMARCB1, SMARCE1, SMARCA2, and PHF6. We show that mutations in ARID1B are the main cause of CSS, accounting for 76\% of identified mutations. ARID1B and SMARCB1 mutations were also found in individuals with the initial diagnosis of NCBRS. These individuals apparently belong to a small subset who display an intermediate CSS/NCBRS phenotype. Our proposed genotype-phenotype correlations are important for molecular screening strategies.
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    Mutations in the interleukin receptor IL11RA cause autosomal recessive Crouzon-like craniosynostosis
    (WILEY, 2013-01-01) Keupp, Katharina; Li, Yun; Vargel, Ibrahim; Hoischen, Alexander; Richardson, Rebecca; Neveling, Kornelia; Alanay, Yasemin; Uz, Elif; Elcioglu, Nursel; Rachwalski, Martin; Kamaci, Soner; Tuncbilek, Gokhan; Akin, Burcu; Grotzinger, Joachim; Konas, Ersoy; Mavili, Emin; Muller-Newen, Gerhard; Collmann, Hartmut; Roscioli, Tony; Buckley, Michael F.; Yigit, Gokhan; Gilissen, Christian; Kress, Wolfram; Veltman, Joris; Hammerschmidt, Matthias; Akarsu, Nurten A.; Wollnik, Bernd
    We have characterized a novel autosomal recessive Crouzon-like craniosynostosis syndrome in a 12-affected member family from Antakya, Turkey, the presenting features of which include: multiple suture synostosis, midface hypoplasia, variable degree of exophthalmos, relative prognathism, a beaked nose, and conductive hearing loss. Homozygosity mapping followed by targeted next-generation sequencing identified a c.479+6T>G mutation in the interleukin 11 receptor alpha gene (IL11RA) on chromosome 9p21. This donor splice-site mutation leads to a high percentage of aberrant IL11RA mRNA transcripts in an affected individual and altered mRNA splicing determined by in vitro exon trapping. An extended IL11RA mutation screen was performed in a cohort of 79 patients with an initial clinical diagnosis of Crouzon syndrome, pansynostosis, or unclassified syndromic craniosynostosis. We identified mutations segregating with the disease in five families: a German patient of Turkish origin and a Turkish family with three affected sibs all of whom were homozygous for the previously identified IL11RA c.479+6T>G mutation
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    RAP1-mediated MEK/ERK pathway defects in Kabuki syndrome
    (AMER SOC CLINICAL INVESTIGATION INC, 2015-01-01) Boegershausen, Nina; Tsai, I.-Chun; Pohl, Esther; Kiper, Pelin Ozlem Simsek; Beleggia, Filippo; Percin, E. Ferda; Keupp, Katharina; Matchan, Angela; Milz, Esther; Alanay, Yasemin; Kayserili, Hulya; Liu, Yicheng; Banka, Siddharth; Kranz, Andrea; Zenker, Martin; Wieczorek, Dagmar; Elcioglu, Nursel; Prontera, Paolo; Lyonnet, Stanislas; Meitinger, Thomas; Stewart, A. Francis; Donnai, Dian; Strom, Tim M.; Boduroglu, Koray; Yigit, Goekhan; Li, Yun; Katsanis, Nicholas; Wollnik, Bernd
    The genetic disorder Kabuki syndrome (KS) is characterized by developmental delay and congenital anomalies. Dominant mutations in the chromatin regulators lysine (K)-specific methyltransferase 2D (KMT2D) (also known as MLL2) and lysine (K)-specific demethylase 6A (KDM6A) underlie the majority of cases. Although the functions of these chromatin-modifying proteins have been studied extensively, the physiological systems regulated by them are largely unknown. Using whole-exome sequencing, we identified a mutation in RAP1A that was converted to homozygosity as the result of uniparental isodisomy (UPD) in a patient with KS and a de novo, dominant mutation in RAP1B in a second individual with a KS-like phenotype. We elucidated a genetic and functional interaction between the respective KS-associated genes and their products in zebrafish models and patient cell lines. Specifically, we determined that dysfunction of known KS genes and the genes identified in this study results in aberrant MEK/ERK signaling as well as disruption of F-actin polymerization and cell intercalation. Moreover, these phenotypes could be rescued in zebrafish models by rebalancing MEK/ERK signaling via administration of small molecule inhibitors of MEK. Taken together, our studies suggest that the KS pathophysiology overlaps with the RASopathies and provide a potential direction for treatment design.