title: Familial asymptomatic macular telangiectasia type 2.
abstract: OBJECTIVE
  To report findings in asymptomatic family members of patients with macular telangiectasia type 2.
  
  
  METHODS
  Prospective, observational, cross-sectional case series.
  
  
  METHODS
  Four patients with symptomatic macular telangiectasia type 2 (index patients) and 5 relatives, including 2 sets of monozygotic twins.
  
  
  METHODS
  Screening of family members of participants in a non-interventional natural history study of macular telangiectasia type 2. Ophthalmologic examination included best-corrected visual acuity testing, fundus biomicroscopy, fluorescein angiography (FA), optical coherence tomography (OCT), and fundus autofluorescence (FAF) imaging.
  
  
  METHODS
  Evidence for macular telangiectasia type 2 in any of the imaging methods used and visual function of the family members studied.
  
  
  RESULTS
  In the first family, 2 of 3 daughters of a severely affected 68-year-old woman had features of macular telangiectasia type 2. Although one of the daughters was diagnosed by biomicroscopic examination, the second daughter was diagnosed only by subtle changes on OCT and FAF imaging. Both affected daughters were asymptomatic and were unaware that they had the condition. In the second family, clinical examination showed that the 60-year-old brother of the 75-year-old index patient obviously was affected, despite a lack of any subjective visual dysfunction. The 65-year-old monozygotic twin of the third index patient showed a slight retinal thinning within a small area temporal to the foveola in both eyes as well as minor staining on FA and a subtle monocular loss of macular pigment. The 56-year-old asymptomatic monozygotic twin of the last proband had opacification of the retina with leakage on FA in the right eye. The fellow eye was unremarkable except for an abnormal FAF signal that was present in both eyes.
  
  
  CONCLUSIONS
  Macular telangiectasia type 2 may be more common than previously assumed, but patients may not seek ophthalmic care if their visual function is normal. The study of these early, asymptomatic cases may yield valuable insights into the pathogenesis of the condition. Further research is warranted to determine whether there is an underlying, dominantly inherited genetic abnormality in macular telangiectasia type 2 of variable penetrance and expressivity.
authors.affiliation: Save Sight Institute, Department of Clinical Ophthalmology and Eye Health, The University of Sydney, Sydney, Australia. mark@eye.usyd.edu.au
authors.forename: Mark C
authors.initials: MC
authors.lastname: Gillies
authors.forename: Meidong
authors.initials: M
authors.lastname: Zhu
authors.forename: Emily
authors.initials: E
authors.lastname: Chew
authors.forename: Daniel
authors.initials: D
authors.lastname: Barthelmes
authors.forename: Edward
authors.initials: E
authors.lastname: Hughes
authors.forename: Haipha
authors.initials: H
authors.lastname: Ali
authors.forename: Frank G
authors.initials: FG
authors.lastname: Holz
authors.forename: Hendrik P N
authors.initials: HP
authors.lastname: Scholl
authors.forename: Peter
authors.initials: P
authors.lastname: Charbel Issa
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D004200:Diseases in Twins / Q000235:genetics*; D005260:Female; D005451:Fluorescein Angiography; D006801:Humans; D008297:Male; D008875:Middle Aged; D010781:Photography; D011446:Prospective Studies; D012164:Retinal Diseases / Q000175:diagnosis / Q000235:genetics* / Q000503:physiopathology; D012171:Retinal Vessels / Q000473:pathology*; D013684:Telangiectasis / Q000175:diagnosis / Q000235:genetics* / Q000503:physiopathology; D041623:Tomography, Optical Coherence; D014430:Twins, Monozygotic / Q000235:genetics*; D014792:Visual Acuity / Q000502:physiology