title: Quantitative Fundus Autofluorescence and Optical Coherence Tomography in PRPH2/RDS- and ABCA4-Associated Disease Exhibiting Phenotypic Overlap.
abstract: OBJECTIVE
  To assess whether quantitative fundus autofluorescence (qAF), a measure of RPE lipofuscin, and spectral-domain optical coherence tomography (SD-OCT) can aid in the differentiation of patients with fundus features that could either be related to ABCA4 mutations or be part of the phenotypic spectrum of pattern dystrophies.
  
  
  METHODS
  Autofluorescence images (30°, 488-nm excitation) from 39 patients (67 eyes) were acquired with a confocal scanning laser ophthalmoscope equipped with an internal fluorescent reference and were quantified as previously described. In addition, horizontal SD-OCT images through the fovea were obtained. Patients were screened for ABCA4 and PRPH2/RDS mutations.
  
  
  RESULTS
  ABCA4 mutations were identified in 19 patients (mean age, 37 ± 12 years) and PRPH2/RDS mutations in 8 patients (mean age, 48 ± 13 years); no known ABCA4 or PRPH2/RDS mutations were found in 12 patients (mean age, 48 ± 9 years). Differentiation of the groups using phenotypic SD-OCT and AF features (e.g., peripapillary sparing, foveal sparing) was not reliable. However, patients with ABCA4 mutations could be discriminated reasonably well from other patients when qAF values were corrected for age and race. In general, ABCA4 patients had higher qAF values than PRPH2/RDS patients, while most patients without mutations in PRPH2/RDS or ABCA4 had qAF levels within the normal range.
  
  
  CONCLUSIONS
  The high qAF levels of ABCA4-positive patients are a hallmark of ABCA4-related disease. The reason for high qAF among many PRPH2/RDS-positive patients is not known; higher RPE lipofuscin accumulation may be a primary or secondary effect of the PRPH2/RDS mutation.
authors.affiliation: Department of Ophthalmology, Columbia University, New York, New York, United States.
authors.forename: Tobias
authors.initials: T
authors.lastname: Duncker
authors.affiliation: Department of Ophthalmology, Columbia University, New York, New York, United States 2Department of Pathology and Cell Biology, Columbia University, New York, New York, United States.
authors.forename: Stephen H
authors.initials: SH
authors.lastname: Tsang
authors.affiliation: Schepens Eye Research Institute and Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States.
authors.forename: Russell L
authors.initials: RL
authors.lastname: Woods
authors.affiliation: Department of Ophthalmology, Columbia University, New York, New York, United States.
authors.forename: Winston
authors.initials: W
authors.lastname: Lee
authors.affiliation: Department of Ophthalmology, Columbia University, New York, New York, United States.
authors.forename: Jana
authors.initials: J
authors.lastname: Zernant
authors.affiliation: Department of Ophthalmology, Columbia University, New York, New York, United States 2Department of Pathology and Cell Biology, Columbia University, New York, New York, United States.
authors.forename: Rando
authors.initials: R
authors.lastname: Allikmets
authors.affiliation: Schepens Eye Research Institute and Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States.
authors.forename: François C
authors.initials: FC
authors.lastname: Delori
authors.affiliation: Department of Ophthalmology, Columbia University, New York, New York, United States 2Department of Pathology and Cell Biology, Columbia University, New York, New York, United States.
authors.forename: Janet R
authors.initials: JR
authors.lastname: Sparrow
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D005451:Fluorescein Angiography; D005654:Fundus Oculi; D006801:Humans; D008268:Macular Degeneration / Q000175:diagnosis / Q000235:genetics; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009887:Ophthalmoscopy; D061848:Optical Imaging; D064531:Peripherins / Q000235:genetics*; D010641:Phenotype; D000080362:Stargardt Disease; D041623:Tomography, Optical Coherence; D055815:Young Adult
chemical_list: C056475:ABCA4 protein, human; D018528:ATP-Binding Cassette Transporters; C578997:PRPH2 protein, human; D064531:Peripherins