title: Clinical and oculomotor characteristics of albinism compared to FRMD7 associated infantile nystagmus.
abstract: OBJECTIVE
  Previous studies have found no difference between nystagmus characteristics associated with idiopathic infantile nystagmus (IIN) and that associated with albinism. The present aim is to compare the oculomotor characteristics and other associated clinical features of albinism and a genetically homogenous group of IIN volunteers where the nystagmus is associated with FRMD7 mutations.
  
  
  METHODS
  Oculomotor characteristics and related clinical features between albinism (n = 52) and idiopathic nystagmus associated with FRMD7 mutations (FRMD7-IIN, n = 83) were compared. The nystagmus characteristics compared included amplitude, frequency, intensity of nystagmus, foveation characteristics, and waveform type. Other clinical features compared were strabismus, stereopsis and anomalous head posture.
  
  
  RESULTS
  The FRMD7-IIN group contained a higher proportion of pendular waveform types compared with the albinism group (P < 0.0001). Nystagmus frequency was significantly lower in albinos (mean = 3.3 Hz, SD = 0.13 Hz) compared with the FRMD7-IIN group (mean = 4.3 Hz, SD = 0.18 Hz) (F = 14.5, P < 0.0001). Strabismus and anomalous head posture was seen in higher proportions in the albinism group, and stereopsis was worse compared with the FRMD7-IIN group (P ≪ 0.0001).
  
  
  CONCLUSIONS
  Differences in nystagmus characteristics associated with albinism and those associated with FRMD7 mutations leading to IIN are described for the first-time. These findings may provide useful information in the future elucidation of mechanisms underlying the nystagmus associated with albinism and idiopathic infantile nystagmus.
authors.affiliation: Ophthalmology Group, University of Leicester, Faculty of Medicine & Biological Sciences, Leicester Royal Infirmary, Leicester, United Kingdom.
authors.forename: Anil
authors.initials: A
authors.lastname: Kumar
authors.forename: Irene
authors.initials: I
authors.lastname: Gottlob
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: McLean
authors.forename: Shery
authors.initials: S
authors.lastname: Thomas
authors.forename: Mervyn G
authors.initials: MG
authors.lastname: Thomas
authors.forename: Frank A
authors.initials: FA
authors.lastname: Proudlock
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016117:Albinism, Ocular / Q000175:diagnosis* / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D003598:Cytoskeletal Proteins / Q000235:genetics*; D003867:Depth Perception; D004596:Electroretinography; D005074:Evoked Potentials, Visual; D005133:Eye Movements / Q000502:physiology; D040181:Genetic Diseases, X-Linked / Q000175:diagnosis* / Q000235:genetics; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics*; D008875:Middle Aged; D009154:Mutation; D020417:Nystagmus, Congenital / Q000175:diagnosis / Q000235:genetics; D009759:Nystagmus, Pathologic / Q000175:diagnosis* / Q000235:genetics; D009801:Oculomotor Muscles / Q000473:pathology*; D013285:Strabismus / Q000175:diagnosis; D041623:Tomography, Optical Coherence
chemical_list: D003598:Cytoskeletal Proteins; C516168:FRMD7 protein, human; D008565:Membrane Proteins