Retinal Arteriolar Tortuosity
Patient Information
Characteristics
Background and History
The retina is nourished by blood flowing through the retinal vasculature. The location and branching patterns of retinal vessels are unique to each individual. Nutrients are supplied to the retina by blood flowing through vessels known as arterioles while the blood returns back to the body in venules. Disease of the retina may alter this pattern. In addition, in several inherited conditions such as the one described here the pathways of the arterioles are unusually tortuous and fragile which may lead to hemorrhages into the retina.
Clinical Correlations
Increased tortuosity of the retinal blood vessels is usually evident in the first decade of life and may become more apparent with aging. Vision is usually normal but some individuals experience episodes of transient vision changes. These may be due to temporary small retinal hemorrhages that may follow even mild exercises. They usually disappear soon afterward without causing permanent damage.
This condition has only been described relatively recently and it is uncertain if one or several conditions are involved. For example, in some families general health is excellent but in others there may be kidney disease, aneurysms (bulging) of the vessels, headaches, and intermittent muscle cramps. There is always a risk of brain strokes from ruptures of the aneurysms.
Genetics
Inheritance
A gene mutation has been found among some patients with increased retinal arteriolar tortuosity. It is responsible for a vertical pattern of inheritance in which parents pass on the vascular disease to their children. Parents with the mutation can expect that half of their offspring will have the same condition.A gene mutation has been found among some patients with increased retinal arteriolar tortuosity. It is responsible for a vertical pattern of inheritance in which parents pass on the vascular disease to their children. Parents with the mutation can expect that half of their offspring will have the same condition.
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 of the retinal vascular pattern is likely to be made by an ophthalmologist. However, a general evaluation is indicated because of the possibility that other conditions such as kidney disease and brain aneurysms are also present. No treatment for the vascular tortuosity is necessary but it would seem prudent to exercise with caution.
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