title: Discordant pursuit asymmetry and esotropia in monozygous twins.
abstract: OBJECTIVE
  To report the relationship between infantile esotropia and asymmetry of monocular pursuit tracking.
  
  
  METHODS
  Observational family case series.
  
  
  METHODS
  A twin pair discordant for infantile esotropia was confirmed by DNA analysis to be monozygous at 99.95% probability. Digitally sampled electro-oculographic recordings of monocular horizontal pursuit eye movements were performed for the twins and their orthophoric father.
  
  
  RESULTS
  Mean directional asymmetry for right and left eyes was 31% and 5% for the esotropic twin, 10% and 8% for the orthophoric twin, and 5% and 6% for the father. The asymmetry was statistically significant only for the deviating right eye of the esotropic twin (P = 0.0217).
  
  
  CONCLUSIONS
  In this family, monocular pursuit asymmetry is probably not a heritable predisposition to infantile esotropia, but a consequence of early strabismus. Discordance of infantile esotropia and pursuit asymmetry in monozygous twins implicates environmental in addition to genetic causes.
authors.affiliation: Department of Ophthalmology, University of California, Los Angeles, USA.
authors.forename: Pradeep
authors.initials: P
authors.lastname: Sharma
authors.forename: Arthur L
authors.initials: AL
authors.lastname: Rosenbaum
authors.forename: Terre
authors.initials: T
authors.lastname: Vives
authors.forename: Wayne W
authors.initials: WW
authors.lastname: Grody
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Demer
mesh_terms: D004247:DNA / Q000032:analysis; D004200:Diseases in Twins; D004585:Electrooculography; D004948:Esotropia / Q000235:genetics* / Q000503:physiopathology; D005260:Female; D006801:Humans; D007223:Infant; D015835:Ocular Motility Disorders / Q000235:genetics* / Q000503:physiopathology; D011698:Pursuit, Smooth / Q000502:physiology; D014430:Twins, Monozygotic / Q000235:genetics*; D015348:Vision, Binocular
chemical_list: D004247:DNA