Abstract
Abstract: :
Purpose: Macular degeneration affects a patient's entire life, so patients with a family history of macular degeneration should consider their condition when making career choices and even when planning a family. To this end, it is vital to differentiate between cases that threaten a patient's vision and those that do not. It is general assumed, that the electrooculogramm (EOG) is a very important criterium for the diagnosis of Best disease. Best disease has an autosmal dominant pattern with intra familial variable expressivity and diminished penetrance. Cause of Best macular dystrophy is a mutation in VMD2 gene, so–called bestrophin gene. Methods: Four members of a family (mother, daughter, and two sons) were examined, and all but one seemed free of the condition at the initial evaluation. Only one of the sons complained of difficulty driving at night. A full clinical evaluation followed, including vision testing, fluorescence angiography, nyctometry, Goldmann perimetry, computerized perimetry (Octopus 1–2–3, Program G1x), and a Panel D 15 color test and electrophysiological examination (EOG, ERG). EOG was elicited according to the method of Arden. Results: The ophthalmological evaluation revealed vitelliform macular dystrophy in all four family members. All the EOG parameters were normal in all cases. Fluorescence angiography revealed ring–shaped regions of hyperfluorescence without an increase in the late stages. Two family members additionally showed several circular lesions. Vision and test results remained stable throughout the two–year follow up, so we diagnosed a patterned macular dystrophy of retinal pigment epithelium. In contrast to this assumption, the genetic analysis of one of the sons indicated a heteroygotic Ala234Val mutation in VMD2 gene, so–called bestrophin gene, wich is associated with Morbus Best (Best macular dystrophy). In addition we found in one case a severe reduction of visus acuity. These findings suggested the existence of Best macular disease in this family. Conclusions: A normal EOG cannot exclude a Best disease. Its nessessary to consider a patterned macular dystrophy of retinal pigment epithelium. Despite genetic analysis, a clear classification is difficult, because heteroygotic Ala234Val mutation in bestrophin gene was described in early– onset vitelliform macular dystrophy and in adult–onset vitelliform macular dystrophy.
Keywords: electrophysiology: clinical • macula/fovea • genetics