title: Cone-rod dystrophy can be a manifestation of Danon disease.
abstract: BACKGROUND
  Danon disease is a neuromuscular disorder with variable expression in the eye. We describe a family with Danon disease and cone-rod dystrophy (CRD).
  
  
  METHODS
  Affected males of one family with Danon were invited for an extensive ophthalmologic examination, including color vision testing, fundus photography, Goldmann perimetry, full-field electroretinogram (ERG), and SD-OCT. Previous ophthalmologic data were retrieved from medical charts. The LAMP2 and RPGR gene were analyzed by direct sequencing.
  
  
  RESULTS
  Two siblings had no ocular phenotype. The third sibling and a cousin developed CRD leading to legal blindness. Visual acuity deteriorated progressively over time, color vision was severely disturbed, and ERG showed reduced photopic and scotopic responses. SD-OCT revealed thinning of the photoreceptor and RPE layer. Visual fields demonstrated central scotoma. The causal mutation was p.Gly384Arg in LAMP2; no mutations were found in RPGR.
  
  
  CONCLUSIONS
  This is the first description of CRD in Danon disease. The retinal phenotype was a late onset but severe dystrophy characterized by loss of photoreceptors and RPE cells. With this report, we highlight the importance of a comprehensive ophthalmologic examination in the clinical work-up of Danon disease.
authors.affiliation: Department of Ophthalmology, Erasmus Medical Center, P.O. Box 2040, NL-3000 CA, Rotterdam, Netherlands. thiadens@hotmail.com
authors.forename: Alberta A H J
authors.initials: AA
authors.lastname: Thiadens
authors.forename: Niki W R
authors.initials: NW
authors.lastname: Slingerland
authors.forename: Ralph J
authors.initials: RJ
authors.lastname: Florijn
authors.forename: Gerhard H
authors.initials: GH
authors.lastname: Visser
authors.forename: Frans C
authors.initials: FC
authors.lastname: Riemslag
authors.forename: Caroline C W
authors.initials: CC
authors.lastname: Klaver
mesh_terms: D000368:Aged; D004596:Electroretinography; D005136:Eye Proteins / Q000235:genetics; D005838:Genotype; D052120:Glycogen Storage Disease Type IIb / Q000175:diagnosis* / Q000235:genetics / Q000503:physiopathology; D006801:Humans; D052119:Lysosomal-Associated Membrane Protein 2; D051907:Lysosomal Membrane Proteins / Q000235:genetics; D008297:Male; D008875:Middle Aged; D020125:Mutation, Missense; D010375:Pedigree; D010641:Phenotype; D016133:Polymerase Chain Reaction; D012174:Retinitis Pigmentosa / Q000175:diagnosis* / Q000235:genetics / Q000503:physiopathology; D035781:Siblings; D041623:Tomography, Optical Coherence; D014792:Visual Acuity / Q000502:physiology; D058609:Visual Field Tests
chemical_list: D005136:Eye Proteins; C497811:LAMP2 protein, human; D052119:Lysosomal-Associated Membrane Protein 2; D051907:Lysosomal Membrane Proteins; C099929:RPGR protein, human