Browsing by Author "Vargel, Ibrahim"

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    Loss-of-Function Mutations in ELMO2 Cause Intraosseous Vascular Malformation by Impeding RAC1 Signaling
    (CELL PRESS, 2016-01-01) Cetinkaya, Arda; Xiong, Jingwei Rachel; Vargel, Ibrahim; Kosemehmetoglu, Kemal; Canter, Halil Ibrahim; Gerdan, Omer Faruk; Longo, Nicola; Alzahrani, Ahmad; Camps, Mireia Perez; Taskiran, Ekim Zihni; Laupheimer, Simone; Botto, Lorenzo D.; Paramalingam, Eeswari; Gormez, Zeliha; Uz, Elif; Yuksel, Bayram; Ruacan, Sevket; Sagiroglu, Mahmut Samil; Takahashi, Tokiharu; Reversade, Bruno; Akarsu, Nurten Ayse
    Vascular malformations are non-neoplastic expansions of blood vessels that arise due to errors during angiogenesis. They are a heterogeneous group of sporadic or inherited vascular disorders characterized by localized lesions of arteriovenous, capillary, or lymphatic origin. Vascular malformations that occur inside bone tissue are rare. Herein, we report loss-of-function mutations in ELMO2 (which translates extracellular signals into cellular movements) that are causative for autosomal-recessive intraosseous vascular malformation (VMOS) in five different families. Individuals with VMOS suffer from life-threatening progressive expansion of the jaw, craniofacial, and other intramembranous bones caused by malformed blood vessels that lack a mature vascular smooth muscle layer. Analysis of primary fibroblasts from an affected individual showed that absence of ELMO2 correlated with a significant downregulation of binding partner DOCK1, resulting in deficient RAC1-dependent cell migration. Unexpectedly, elmo2-knockout zebrafish appeared phenotypically normal, suggesting that there might be human-specific ELMO2 requirements in bone vasculature homeostasis or genetic compensation by related genes. Comparative phylogenetic analysis indicated that elmo2 originated upon the appearance of intramembranous bones and the jaw in ancestral vertebrates, implying that elmo2 might have been involved in the evolution of these novel traits. The present findings highlight the necessity of ELMO2 for maintaining vascular integrity, specifically in intramembranous bones.
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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