title: Transgrediens pachyonychia congenita (PC): case series of a nonclassical PC presentation.
abstract: BACKGROUND
  Pachyonychia congenita (PC) is a rare keratin disorder that typically presents with nail dystrophy and focal plantar keratoderma. We present seven cases of PC with transgrediens involvement of the dorsal feet.
  
  
  OBJECTIVE
  To document the extension of their disease to the dorsum of the feet in patients with mutation-confirmed PC, to report the natural history of PC with such transgrediens involvement, to generate hypotheses regarding aetiology, and to suggest prevention and treatment modalities.
  
  
  METHODS
  Genetically confirmed cases of PC with transgrediens foot involvement were verified through the International Pachyonychia Congenita Research Registry (IPCRR) and characterized via telephone survey and photography.
  
  
  RESULTS
  Seven patients with PC in the IPCRR were confirmed to have transgrediens lesions on the dorsal feet (six KRT6A mutations; one KRT16 mutation). Six cases had pre-existing nontransgrediens keratoderma and all cases reported standing, wearing shoes, foot moisture, and/or infection as exacerbating or predisposing factors. Improvement, reported in six cases, was attributed to use of antibiotics or gentian violet, or improved footwear.
  
  
  CONCLUSIONS
  Transgrediens involvement of the dorsal feet is a rare manifestation of mutation-confirmed PC and may be more common in patients who carry a KRT6A mutation. Trauma, friction, infection and wound healing may exacerbate or predispose toward transgrediens lesions. It remains to be proven whether transgrediens-associated infection is causal or represents a primary or secondary process. Patients with PC who develop transgrediens lesions may benefit from fungal and bacterial cultures, followed by appropriate antimicrobial treatments. Efforts to decrease skin friction and moisture may also improve and/or prevent transgrediens spread.
authors.affiliation: Department of Dermatology, University of Utah, Huntsman Cancer Institute, 2000 Circle of Hope, Rm 5242, Salt Lake City, UT 84112, USA.
authors.forename: K
authors.initials: K
authors.lastname: Harris
authors.forename: P R
authors.initials: PR
authors.lastname: Hull
authors.forename: C D
authors.initials: CD
authors.lastname: Hansen
authors.forename: F J D
authors.initials: FJ
authors.lastname: Smith
authors.forename: W H I
authors.initials: WH
authors.lastname: McLean
authors.forename: J L
authors.initials: JL
authors.lastname: Arbiser
authors.forename: S A
authors.initials: SA
authors.lastname: Leachman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005533:Foot Dermatoses / Q000175:diagnosis* / Q000235:genetics; D006579:Heterozygote; D006801:Humans; D053536:Keratin-16 / Q000235:genetics; D053553:Keratin-6 / Q000235:genetics; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics; D053549:Pachyonychia Congenita / Q000175:diagnosis* / Q000235:genetics
chemical_list: C507431:KRT16 protein, human; C507569:KRT6A protein, human; D053536:Keratin-16; D053553:Keratin-6