title: A prospective study of filaggrin null mutations in keratoconus patients with or without atopic disorders.
abstract: BACKGROUND
  Atopic dermatitis (AD) is significantly associated with keratoconus (KC). An inherited component for KC has been suggested. Filaggrin (FLG) mutations are a strong genetic risk factor for AD. Since filaggrin is also expressed in the corneal epithelium, we hypothesized a common aetiology for ichthyosis vulgaris (IV), AD and KC.
  
  
  OBJECTIVE
  We examined the prevalence of AD and IV in a KC population. We also studied the expression of filaggrin in normal and KC cornea and analysed 2 prevalent loss-of-function FLG alleles (R501X and 2282del4) in a KC population. Finally we examined whether the population with KC and FLG mutations had specific clinical characteristics.
  
  
  RESULTS
  Of 89 KC patients, 38 had current or a history of AD and/or IV. Five patients were carriers of at least 1 FLG mutant allele and had a clinical diagnosis of AD and IV with a severer KC.
  
  
  CONCLUSIONS
  The low frequency of FLG mutations is surprising since 42.7% of our KC population had AD associated or not with IV; the expected frequency would have been 12-15%, based on our previous studies. Further studies are required to look at other possible FLG mutations or other candidate genes.
authors.affiliation: Department of Dermatology, National Reference Centre for Rare Skin Disorders, CHU de Bordeaux, Bordeaux, France. catherine.droitcourt@gmail.com
authors.forename: C
authors.initials: C
authors.lastname: Droitcourt
authors.forename: D
authors.initials: D
authors.lastname: Touboul
authors.forename: C
authors.initials: C
authors.lastname: Ged
authors.forename: K
authors.initials: K
authors.lastname: Ezzedine
authors.forename: M
authors.initials: M
authors.lastname: Cario-André
authors.forename: H
authors.initials: H
authors.lastname: de Verneuil
authors.forename: J
authors.initials: J
authors.lastname: Colin
authors.forename: A
authors.initials: A
authors.lastname: Taïeb
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003876:Dermatitis, Atopic / Q000453:epidemiology / Q000235:genetics*; D005260:Female; D000091344:Filaggrin Proteins; D020022:Genetic Predisposition to Disease / Q000453:epidemiology; D006801:Humans; D007381:Intermediate Filament Proteins / Q000235:genetics*; D007640:Keratoconus / Q000453:epidemiology / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D015995:Prevalence; D011446:Prospective Studies; D055815:Young Adult
chemical_list: C000717249:FLG protein, human; D000091344:Filaggrin Proteins; D007381:Intermediate Filament Proteins