title: Characterizing the phenotype and genotype of a family with occult macular dystrophy.
abstract: OBJECTIVE
  To characterize the phenotype of a white patient with occult macular dystrophy (OMD) and her clinically unaffected family members and to determine whether similar mutations were present in the RP1L1 gene in this family. Occult macular dystrophy is a rare macular dystrophy with central cone dysfunction hidden behind a normal fundus appearance that has been attributed to a mutation in the retinitis pigmentosa 1-like 1 (RP1L1) gene in 4 Japanese families.
  
  
  METHODS
  In this observational cross-sectional study of 1 white family with OMD, patients meeting the clinical criteria for OMD and their family members were evaluated by use of multifocal electroretinography, the Farnsworth D-15 color vision test, automated perimetry, spectral-domain optical coherence tomography (SD-OCT), fundus autofluorescence, and fundus photography. Fluorescein angiography was performed only on the proband. Members of this family were screened for genetic mutations in the RP1L1 gene.
  
  
  RESULTS
  In the family studied, the clinically affected proband was noted to have loss of the foveal outer segments and absence of bowing of the inner segment/outer segment junction on SD-OCT scans. In addition, 1 clinically unaffected family member also demonstrated loss of the foveal photoreceptor outer segments and, therefore, decreased bowing of the inner segment/outer segment junction on SD-OCT scans. The fundus autofluorescence images of the eyes of the proband and her family members were normal. Although mutations in the RP1L1 gene have been identified in sporadic and autosomal dominant OMD pedigrees, no mutations in the RP1L1 gene were found in any of the participants.
  
  
  CONCLUSIONS
  Loss of the outer segments of foveal photoreceptors can be detected and quantified by use of SD-OCT in patients with OMD. Similar findings are present in some clinically unaffected family members and may represent subclinical manifestations of the disease. Although mutations in the RP1L1 gene have been described in several Japanese families with OMD, there were no such mutations in this white family of European descent, which suggests that inherited OMD is a genetically heterogeneous disorder.
authors.forename: Connie J
authors.initials: CJ
authors.lastname: Chen
authors.forename: Hendrik P N
authors.initials: HP
authors.lastname: Scholl
authors.forename: David G
authors.initials: DG
authors.lastname: Birch
authors.forename: Takeshi
authors.initials: T
authors.lastname: Iwata
authors.forename: Neil R
authors.initials: NR
authors.lastname: Miller
authors.forename: Morton F
authors.initials: MF
authors.lastname: Goldberg
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D004596:Electroretinography; D005136:Eye Proteins / Q000235:genetics*; D005260:Female; D005838:Genotype; D006801:Humans; D008266:Macula Lutea / Q000473:pathology; D008268:Macular Degeneration / Q000235:genetics* / Q000473:pathology*; D008297:Male; D010641:Phenotype; D041623:Tomography, Optical Coherence; D044465:White People
chemical_list: D005136:Eye Proteins; C474032:RP1L1 protein, human