Original ArticlesA novel mutation in MYCN gene causing congenital absence of the flexor pollicis longus tendon as an unusual presentation of Feingold syndrome 1Peleg, Amira,,b,,*; Kurolap, Alinab,,c,,*; Sagi-Dain, Lenaa,,b; Larom-Khan, G.a; Adir, V.a,,b; Mory, Adib,,c; Paperna, Tamarc; Shuldiner, A.R.d; Gonzaga-Jauregui, C.d; Adir, Noame; Baris Feldman, Hagitb,,c; Wollstein, R.b,,fAuthor Information aThe Genetics Institute, Lady Davis Carmel Medical Center bThe Ruth and Bruce Rappaport Faculty of Medicine, Technion – Israel Institute of Technology cThe Genetics Institute, Rambam Health Care Campus, Haifa, Israel dRegeneron Genetics Center, Tarrytown, New York, USA eThe Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa, Israel fNew York University School of Medicine, New York, USA *Amir Peleg and Alina Kurolap contributed equally to the writing of this article. Received 30 December 2019 Accepted 14 July 2020 Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's website, http://www.clindysmorphol.com. Correspondence to Amir Peleg, MD, Carmel Hospital, Haifa, Israel, Tel: +972 4 8250344; e-mail: [email protected] Clinical Dysmorphology: April 2021 - Volume 30 - Issue 2 - p 71-75 doi: 10.1097/MCD.0000000000000342 Buy SDC Metrics Abstract Feingold syndrome 1 (FGLDS1) is an autosomal dominant malformation syndrome, characterized by skeletal anomalies, microcephaly, facial dysmorphism, gastrointestinal atresias and learning disabilities. Mutations in the MYCN gene are known to be the cause of this syndrome. Congenital absence of the flexor pollicis longus (CAFPL) tendon is a rare hand anomaly. Most cases are sporadic and no genetic variants have been described associated with this abnormality. We describe here a pedigree combining familial CAFPL tendon as a feature of FGLDS1. Molecular analyses of whole exome sequence data in five affected family members spanning three generations of this family revealed a novel mutation in the MYCN gene (c.1171C>T; p.Arg391Cys). Variants in MYCN have not been published in association with isolated or syndromic CAFPL tendon, nor has this been described as a skeletal feature of Feingold syndrome. This report expands on the clinical and molecular spectrum of MYCN-related disorders and highlights the importance of MYCN protein in normal human thumb and foramen development. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.