Macular Edema, Autosomal Dominant Cystoid
Patient Information
Characteristics
Background and History
The macula is a specialized area of the retina which contains the highest concentration of rods and cones (the light sensing cells that respond to light as the first step in seeing). This area is used to give us the highest resolution of vision so any disease of the macula leads to symptoms early. Many conditions (both hereditary and nonhereditary) lead to macular damage.
Clinical Correlations
Only a few families have been reported and little is known about its natural history. The small blood vessels in the retina, especially in the macula, leak excess fluid which leads to damage of the rods and cones. This may occur early in life but visual disturbances are often not reported until the second decade of life. This is a progressive disorder and more damage to vision takes place as patients age. Far sightedness, crossing of the eyes, and mild disturbances in color vision are often present.
Genetics
Inheritance
This is an autosomal dominant condition which is passed directly from parent to child. Someone with dominant cystoid macular edema can expect that each of their children have a 50% risk of developing the same disorder.
Pedigree
Autosomal dominant
Autosomal dominant disorders require only one mutation for the disease to be expressed. Since an affected parent has two chromosomes, only one of which has the mutant gene, parents can expect that half (50%) of their children will receive that one and inherit the disease. It is common for individuals that inherit the mutation, however, to not have evidence of the disease (nonpenetrance).
Autosomal dominant inheritance leads to a vertical pattern of transmission
Diagnosis and Prognosis
An ophthalmologist is usually the one to make this diagnosis following a complete examination of the retina. Several tests can be used to distinguish this condition from others which appear superficially similar. An electroretinogram (ERG) can be helpful. Sometimes a fluorescein dye is injected into a vein followed by rapid sequence photography of the retinal circulation which can reveal fluid leakage.
No specific treatment is available but low vision aids should be helpful, at least in early stages of the disorder. No systemic abnormalities have been reported and longevity is normal.
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