The macula is a specialized area of the retina. It is used for high resolution vision such as reading, since it contains the highest density of light receptors (rods and cones). The macula is frequently involved in disorders of the retina, both acquired and inherited. When diseased, functional vision useful in tasks of daily living is often lost.
Progressive deterioration of macular function is perhaps most common among older individuals where it is called ‘age-related macular degeneration’. This is most common among individuals over the age of 70 and it is the result of multiple genetic and environmental factors. In the condition described in this entry, the onset of disease is much earlier, as in the fourth and fifth decades and it seems to be caused by a single gene mutation.
Visual symptoms such as distortion of images have been reported as early as the fourth decade. Individuals from the single reported family were found to have changes in retina and choroid in the fifth decade although, since they were not examined earlier, it is possible that evidence of macular degeneration was present earlier. The pigmented layer of the retina seems to be most affected.
No treatment is available in the early stages but standard therapies for abnormal vessel proliferation can be used when new vessels appear.
This is an autosomal dominant condition that is passed from parent to child. Affected parents of both sexes have a 50% chance to pass the responsible gene mutation to each child.
An ophthalmologist (medical eye doctor) is the most likely to detect this variant of macular degeneration when the clinical features are found in patient under the age of 50 years. Vision is highly variable depending upon the stage of disease. Patients need to have frequent eye examinations throughout their lives as the retinal degeneration is progressive. In early stages, low vision devices may be helpful. Evidence of new blood vessel growth must be evaluated and treated as needed.
There are no associated signs or symptoms elsewhere in the body and longevity is not impacted.