title: Systemic epidermal nevus with involvement of the oral mucosa due to FGFR3 mutation.
abstract: BACKGROUND
  Epidermal nevi (EN) represent benign congenital skin lesions following the lines of Blaschko. They result from genetic mosaicism, and activating FGFR3 and PIK3CA mutations have been implicated.
  
  
  METHODS
  We report a female patient with a systemic keratinocytic nevus also involving the oral mucosa. Molecular genetic analysis revealed a mosaicism of the FGFR3 hotspot mutation R248C in the EN lesions of the skin and of the oral mucosa. The detection of the R248C mutation in a proportion of blood leukocytes and a slight scoliosis suggest an EN syndrome.
  
  
  CONCLUSIONS
  Our results show that activating FGFR3 mutations can also affect the oral mucosa and that extracutaneous manifestations of EN syndrome can be subtle. We highlight the theoretical risk of the patient having an offspring with thanatophoric dysplasia as gonadal mosaicism for the R248C mutation cannot be excluded.
authors.affiliation: Department of Dermatology and Allergy Centre, Odense University Hospital, 5000 Odense, Denmark. anette.bygum@ouh.regionsyddanmark.dk
authors.forename: Anette
authors.initials: A
authors.lastname: Bygum
authors.forename: Christina R
authors.initials: CR
authors.lastname: Fagerberg
authors.forename: Ole J
authors.initials: OJ
authors.lastname: Clemmensen
authors.forename: Britta
authors.initials: B
authors.lastname: Fiebig
authors.forename: Christian
authors.initials: C
authors.lastname: Hafner
mesh_terms: D004817:Epidermis / Q000473:pathology*; D005260:Female; D006801:Humans; D009030:Mosaicism; D009061:Mouth Mucosa / Q000473:pathology*; D020125:Mutation, Missense / Q000235:genetics*; D009506:Nevus / Q000235:genetics*; D051498:Receptor, Fibroblast Growth Factor, Type 3 / Q000235:genetics*
chemical_list: C496365:FGFR3 protein, human; D051498:Receptor, Fibroblast Growth Factor, Type 3