title: The optic nerve head in congenital fibrosis of the extraocular muscles.
abstract: OBJECTIVE
  Optic nerve head abnormalities have been reported in some patients with congenital fibrosis of the extraocular muscles (CFEOM). This study prospectively assesses optic nerve head appearance in a consecutive CFEOM cohort.
  
  
  METHODS
  All patients with CFEOM referred between 2006 and 2010 and who were mature enough to cooperate with fundus photography were included. Fundus photographs were reviewed with attention to optic nerve head features (eg, cupping >0.6, asymmetric cupping >0.3, optic nerve hypoplasia). Interested participants had CFEOM candidate gene analysis (KIF21A, TUBB3, PHOX2A) for genetic counseling purposes.
  
  
  RESULTS
  Ten CFEOM patients (five CFEOM1, five CFEOM3, age range 5-23 years) from eight families (all consanguineous but one) participated. All 10 patients had notable disc excavation (5) or optic nerve hypoplasia (5). CFEOM candidate gene analysis was performed in all patients and revealed a heterozygous p.R954W KIF21A mutation only in the patient who was not from a consanguineous family.
  
  
  CONCLUSIONS
  Our observations suggest the optic nerve head can be affected by the orbital dysinnervation that occurs in CFEOM. Because careful clinical optic nerve head assessment is difficult in young patients with CFEOM and associated large angle incomitant strabismus, optic nerve head abnormalities may be under-diagnosed. The absence of mutations in known CFEOM genes in our cohort of consanguineous families suggests further genetic heterogeneity of this group of conditions.
authors: Division of Pediatric Ophthalmology, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia. arif.khan@mssm.edu
authors: Arif O
authors: AO
authors: Khan
authors: Jameela
authors: J
authors: Shinwari
authors: Aisha
authors: A
authors: Omar
authors: Dania
authors: D
authors: Khalil
authors: Mohammad
authors: M
authors: Al-Anazi
authors: Abdullah
authors: A
authors: Al-Amri
authors: Nada A
authors: NA
authors: Al-Tassan
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003241:Consanguinity; D005260:Female; D005355:Fibrosis / Q000151:congenital; D006801:Humans; D016547:Kinesins / Q000235:genetics; D008297:Male; D009154:Mutation; D009801:Oculomotor Muscles / Q000294:innervation / Q000473:pathology*; D009898:Optic Disk / Q000002:abnormalities*; D009901:Optic Nerve Diseases / Q000175:diagnosis* / Q000235:genetics; D013285:Strabismus / Q000175:diagnosis / Q000235:genetics; D055815:Young Adult
chemical_list: C119023:KIF21A protein, human; D016547:Kinesins