Arda Cetinkaya 1 , Jingwei Rachel Xiong 2 , İbrahim Vargel 3 , Kemal Kösemehmetoğlu 4 , Halil İbrahim Canter 5 , Ömer Faruk Gerdan 6 , Nicola Longo 7 , Ahmad Alzahrani 8 , Mireia Perez Camps 2 , Ekim Zihni Taskiran 1 , Simone Laupheimer 2 , Lorenzo D Botto 7 , Eeswari Paramalingam 2 , Zeliha Gormez 6 , Elif Uz 9 , Bayram Yuksel 10 , Şevket Ruacan 11 , Mahmut Şamil Sağıroğlu 6 , Tokiharu Takahashi 12 , Bruno Reversade 13 , Nurten Ayse Akarsu 14
Aug 04 2016
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.