133. Focal Dermal Hypoplasia

  1. Alan D. Irvine MD, FRCPI, FRCP3,4,
  2. Peter H. Hoeger MD5,6 and
  3. Albert C. Yan MD, FAAP, FAAD7,8
  1. Amarilis Sanchez-Valle MD1,
  2. V. Reid Sutton MD2 and
  3. Ignatia B. Van den Veyver MD2

Published Online: 24 MAY 2011

DOI: 10.1002/9781444345384.ch133

Harper's Textbook of Pediatric Dermatology, Volume 1, 2, Third Edition

Harper's Textbook of Pediatric Dermatology, Volume 1, 2, Third Edition

How to Cite

Sanchez-Valle, A., Sutton, V. R. and Van den Veyver, I. B. (2011) Focal Dermal Hypoplasia, in Harper's Textbook of Pediatric Dermatology, Volume 1, 2, Third Edition (eds A. D. Irvine, P. H. Hoeger and A. C. Yan), Wiley-Blackwell, Oxford, UK. doi: 10.1002/9781444345384.ch133

Editor Information

  1. 3

    Trinity College, Dublin, Ireland

  2. 4

    Our Lady's Children's Hospital, Dublin, Ireland

  3. 5

    University of Hamburg, Hamburg, Germany

  4. 6

    Catholic Children's Hospital Wilhelmstift, Hamburg, Germany

  5. 7

    University of Pennsylvania School of Medicine, Philadelphia, PA, USA

  6. 8

    The Children's Hospital of Philadelphia, Philadelphia, PA, USA

Author Information

  1. 1

    Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, TX, USA

  2. 2

    Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX, USA

Publication History

  1. Published Online: 24 MAY 2011
  2. Published Print: 3 JUN 2011

ISBN Information

Print ISBN: 9781405176958

Online ISBN: 9781444345384



  • aplasia cutis;
  • Blaschko's lines;
  • ectomesodermal;
  • focal dermal hypoplasia;
  • mosaicism;
  • PORCN;
  • skeletal defects;
  • striations;
  • WNT signalling;
  • X chromosome


Focal dermal hypoplasia is a rare congenital mesoectodermal disorder, first described in 1962 by Goltz et al., who coined the name ‘focal dermal hypoplasia’ to describe the focal areas of decreased connective tissue in the skin exposing subcutaneous fat. The combination of typical skin manifestations and one or more characteristic skeletal, ocular, dental and facial features supports a clinical diagnosis of focal dermal hypoplasia. Other phenotypic features include abdominal wall defects, urogenital abnormalities and diaphragmatic hernia. Most affected individuals are females; mildly affected males who can have severely affected daughters represent a small minority of cases. Focal dermal hypoplasia is caused by mutations in PORCN, an essential gene on the X chromosome that is subject to X inactivation and encodes an important regulator of WNT protein secretion. Disrupted WNT signalling probably explains the various phenotypic features of focal dermal hypoplasia, while varying levels of X inactivation and somatic mosaicism for mutations may explain the variable severity.