title: Recent progress in understanding congenital cranial dysinnervation disorders.
abstract: BACKGROUND
  In 2002, the new term congenital cranial dysinnervation disorder (CCDD) was proposed as a substitute for the traditional concept of congenital fibrosis of the extraocular muscles (CFEOM) based on mounting genetic, neuropathologic, and imaging evidence, suggesting that many, if not all, of these disorders result from a primary neurologic maldevelopment rather than from a muscle abnormality. This report provides an update 8 years after that original report.
  
  
  METHODS
  Review of pertinent articles published from January 2003 until June 2010 describing CCDD variants identified under PubMed MeSH terms congenital fibrosis of the extraocular muscles, congenital cranial dysinnervation disorders, individual phenotypes included under the term CCDD, and congenital ocular motility disorders.
  
  
  RESULTS
  At present, a total of 7 disease genes and 10 phenotypes fall under the CCDD umbrella. A number of additional loci and phenotypes still await gene elucidation, with the anticipation that more syndromes and genes will be identified in the future. Identification of genes and their function, along with advances in neuroimaging, have expanded our understanding of the mechanisms underlying several anomalous eye movement patterns.
  
  
  CONCLUSIONS
  Current evidence still supports the concept that the CCDDs are primarily due to neurogenic disturbances of brainstem or cranial nerve development. Several CCDDs are now known to have nonophthalmologic associations involving neurologic, neuroanatomic, cerebrovascular, cardiovascular, and skeletal abnormalities.
authors.affiliation: Department of Ophthalmology, College of Medicine, King Saud University, and King Abdulaziz University Hospital, Riyadh, Saudi Arabia. darrenoystreck@ymail.com
authors.forename: Darren T
authors.initials: DT
authors.lastname: Oystreck
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Engle
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Bosley
mesh_terms: D002658:Developmental Disabilities / Q000175:diagnosis* / Q000235:genetics / Q000503:physiopathology; D005355:Fibrosis; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D015835:Ocular Motility Disorders / Q000175:diagnosis* / Q000235:genetics / Q000503:physiopathology