Familial Internal Retinal Membrane Dystrophy
Patient Information
Characteristics
Background and History
This is a rare inherited form of retinal degeneration in which the retina (light sensing tissue lining the inside of the eye) degenerates.
Clinical Correlations
Vision is normal until about age 50 years when it progressively worsens. The retina has an unusual glistening appearance with small cysts present. The major changes occur in the macula which is a specialized are of the retina containing the greatest concentration of light sensing cells called the rods and cones. Since this is the area that we use for our most detailed seeing tasks, our vision is most affected when it is damaged. The remainder of the eye is relatively normal.
Individuals with this condition are otherwise healthy.
Genetics
Inheritance
Only a few families have been reported and the pattern of inheritance is characteristic of autosomal dominant inheritance. A parent with this condition can expect that on average half of his or her children will inherit the same condition. No responsible gene change has been identified.
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
The diagnosis is made by an ophthalmologist. No effective treatment is known but low vision aids could be helpful.
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