Accepted Article This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1111/pcmr.12761 This article is protected by copyright. All rights reserved. MR. MAXIMILIAN ULRICH (Orcid ID : 0000-0002-5022-7874) Article type : Letter to the Editor Detection of a multi-lineage mosaic NRAS mutation c.181C>A (p.Gln61Lys) in an individual with a complex congenital nevus syndrome Maximilian Ulrich 1 , Sigrid Tinschert 2 , Eberhard Siebert 3 , Ingolf Franke 4 , Thomas Tüting 4 , Jens Ulrich 5 , Denny Schanze 1 , Ilse Wieland 1 , Martin Zenker 1 1 Institute of Human Genetics, University Hospital Otto-von-Guericke-University, Magdeburg, Germany; 2 Medical Faculty Carl Gustav Carus, Technical University of Dresden, Dresden, Germany and Division of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria; 3 Institute of Neuroradiology, Charité Centrum, Berlin, Germany; 4 Department of Dermatology, University Hospital Magdeburg, Magdeburg, Germany; 5 Klinik für Dermatologie und Venerologie, Harzklinikum Dorothea Christiane Erxleben, Quedlinburg, Germany. Correspondence: Martin Zenker, Institute of Human Genetics, University Hospital Otto-von Guericke-University, Leipziger Str. 44, 39120 Magdeburg, Germany; Tel: +49 391 6715062; Fax: +49 3916716066; Email: martin.zenker@med.ovgu.de Keywords: Encephalocraniocutaneous lipomatosis, Congenital melanocytic nevus, NRAS, Mosaic RASopathies Running Head: multi-lineage mosaic NRAS mutation c.181C>A Dear Editor, Mosaic RASopathies constitute a clinically and genetically heterogeneous group of non-inherited congenital (neuro)cutaneous disorders caused by postzygotic mutations in genes encoding components of the RAS-MAPK signaling pathway (Luo & Tsao, 2014). There are striking genotype- phenotype correlations within this group but also clinical features overlapping between distinct disorders. Congenital melanocytic nevi (CMN) are the most common lesions falling into the category of mosaic RASopathies. The term congenital melanocytic nevus syndrome (CMNS, MIM #137550)