title: Phenotypic spectrum of autosomal recessive cone-rod dystrophies caused by mutations in the ABCA4 (ABCR) gene.
abstract: OBJECTIVE
  To describe the phenotype of 12 patients with autosomal recessive or isolated cone-rod types of progressive retinal degeneration (CRD) caused by mutations in the ABCA4 gene.
  
  
  METHODS
  The charts of patients who had originally received a diagnosis of isolated or autosomal recessive CRD were reviewed after molecular analysis revealed mutations in the ABCA4 gene.
  
  
  RESULTS
  In two of the patients both the photopic and scotopic electroretinogram were nonrecordable. In the remainder, the photopic cone b-wave amplitudes appeared to be more seriously affected than the scotopic rod b-wave amplitudes. Although the clinical presentation was heterogeneous, all patients experienced visual loss early in life, impaired color vision, and a central scotoma. Fundoscopy revealed evidence of early-onset maculopathy, sometimes accompanied by involvement of the retinal periphery in the later stages of the disease.
  
  
  CONCLUSIONS
  Mutations in the ABCA4 gene are the pathologic cause of the CRD-like dystrophy in these patients, and the resultant clinical pictures are complex and heterogeneous. Given this wide clinical spectrum of CRD-like phenotypes associated with ABCA4 mutations, detailed clinical subclassifications are difficult and may not be very useful.
authors.affiliation: Department of Ophthalmology, University Medical Centre Nijmegen, Nijmegen, The Netherlands. b.klevering@ohk.azn.nl
authors.forename: B Jeroen
authors.initials: BJ
authors.lastname: Klevering
authors.forename: Anita
authors.initials: A
authors.lastname: Blankenagel
authors.forename: Alessandra
authors.initials: A
authors.lastname: Maugeri
authors.forename: Frans P M
authors.initials: FP
authors.lastname: Cremers
authors.forename: Carel B
authors.initials: CB
authors.lastname: Hoyng
authors.forename: Klaus
authors.initials: K
authors.lastname: Rohrschneider
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D003118:Color Perception; D004596:Electroretinography; D005260:Female; D005451:Fluorescein Angiography; D005654:Fundus Oculi; D005808:Genes, Recessive; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010641:Phenotype; D020419:Photoreceptor Cells, Vertebrate / Q000473:pathology*; D012162:Retinal Degeneration / Q000235:genetics* / Q000473:pathology; D014792:Visual Acuity
chemical_list: C056475:ABCA4 protein, human; D018528:ATP-Binding Cassette Transporters