title: Congenital adrenal hyperplasia due to 21-hydroxylase deficiency associated with bilateral keratoconus.
abstract: OBJECTIVE
  To report a clinical association between congenital adrenal hyperplasia and keratoconus.
  
  
  METHODS
  Observational case report.
  
  
  METHODS
  Two 25-year-old dizygotic female twins were retrospectively studied. Clinical history, hormonal serologic profile, complete ophthalmologic examination, and Holladay Diagnostic Summary variables were evaluated. In the course of a 15-month follow-up period, a progression of the corneal disease was observed.
  
  
  RESULTS
  In both twins a diagnosis of nonclassical congenital adrenal hyperplasia, due to 21-hydroxylase deficiency, was established when they were 21 years old. In one subject, the computed corneal topographic analyses diagnosed an asymmetric keratoconus in both eyes. A progressive form of fruste central keratoconus was also documented in her sister.
  
  
  CONCLUSIONS
  Congenital adrenal hyperplasia may be associated with keratoconus. An abnormal steroidogenic pathway, affecting the normal development of the cornea, could induce stromal abnormalities that lead to corneal ectasia.
authors.affiliation: Department of Ophthalmology, University of Ferrara, Ferrara, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Incorvaia
authors.forename: Francesco
authors.initials: F
authors.lastname: Parmeggiani
authors.forename: Ciro
authors.initials: C
authors.lastname: Costagliola
authors.forename: Paolo
authors.initials: P
authors.lastname: Perri
authors.forename: Marzia
authors.initials: M
authors.lastname: Tittoni
authors.forename: Adolfo
authors.initials: A
authors.lastname: Sebastiani
mesh_terms: D000312:Adrenal Hyperplasia, Congenital / Q000175:diagnosis / Q000201:enzymology / Q000235:genetics*; D000328:Adult; D003315:Cornea / Q000473:pathology*; D019781:Corneal Topography; D004200:Diseases in Twins / Q000175:diagnosis / Q000235:genetics*; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000175:diagnosis / Q000201:enzymology / Q000235:genetics*; D012189:Retrospective Studies; D013255:Steroid 21-Hydroxylase / Q000378:metabolism*; D014429:Twins, Dizygotic
chemical_list: D013255:Steroid 21-Hydroxylase