Could You Have an Inherited Retinal Disease?
When you look around your family, you become aware of many similarities: hair color, height, expressions, and personality traits, to name a few.
Unfortunately, genetics also play a significant role in eye disease. By learning more about certain inherited retinal diseases, you begin the path that leads toward better vision and total eye health. Not all conditions manifest themselves immediately, so visit your eye specialist early to assess your risk level.
Unlike macular degeneration that may develop with age, genetic retinal disease occurs when a mutated gene causes vision loss. The following conditions are inherited:
Leber Congenital Amaurosis
This eye disorder occurs as the result of multiple genetic mutations that disrupt normal retinal development during infancy. The result may be either gradual or sudden vision loss. In reality, there are more than 13 disease types of this disorder, each manifesting different vision loss patterns.
Even one copy of a mutated gene per cell can cause this retinal disorder. Additionally, new mutations may arise, which means it’s possible to develop the disease even with no family history.
Although each case is different, leber congenital amaurosis often exhibits the following symptoms or conditions:
- Involuntary or rapid eye movement
- Light sensitivity
- Abnormal farsightedness
- Slow pupil reactivity
- Keratoconus (cone-shaped, thin cornea)
Additionally, if your child presses, pokes, or rubs eyes regularly, check with your eye specialist.
When retinal tissues separate into layers, this is called retinoschisis. The disease usually occurs in childhood, impacting one in up to 25,000 persons.
Further, because the abnormal or mutated gene generally focuses on a single X chromosome, it primarily affects young boys and men. Even if women have one abnormal X chromosome, it’s likely that their second X chromosome will be normal, canceling out the effect.
At times, this condition may be confused with lazy eye. If your eye doctor is unfamiliar with retinal diseases, be sure to see a specialist to rule out retinoschisis. The two most common symptoms include decreased central vision and decreased peripheral vision. If vision doesn’t improve even with glasses, your doctor may suspect retinoschisis.
This genetic condition shouldn’t be confused with the degenerative form of the disease, which occurs with age.
Retinitis Pigmentosa and Usher Syndrome
Although these two diseases are separate conditions, one often accompanies the other. Here are the basic descriptions of each:
- Retinitis Pigmentosa – Called RP for short, retinitis pigmentosa affects light sensitivity by breaking down the retina’s photoreceptors. Persons with RP usually notice night blindness, peripheral vision loss, and even tunnel vision. Rods are more often affected than cones. If the cones are affected, patients usually notice central vision loss.
- Usher Syndrome – Unlike RP, Usher syndrome can affect hearing as well as vision. However, it is associated with RP, and manifests commonly in types 1 and 2, plus the less-common type 3.
While RP is generally a genetic disease, it may also show up as part of other diseases. Usher syndrome is passed on by just one carrier, even if he or she has normal vision or hearing.
Like RP and Usher syndrome, Stargardt disease impacts the photoreceptor cells, as well as the retinal pigment skin cells. It is considered to be an inherited form of juvenile macular degeneration.
If a child experiences changes in central vision, talk to a specialist to schedule an exam. If the doctor notices yellow flecks around the macula, he or she may suspect Stargardt disease. These yellow flecks signal an abnormal buildup of a fatty material called lipofuscin.
Like many other retinal diseases listed thus far, this condition causes vision loss that doesn’t respond to prescriptive correction. Unlike many other genetic eye conditions, Stargardt disease requires both parents to have one abnormal and one normal gene.
This particular eye disorder is rare, but serious. It progresses from night blindness all the way to complete vision loss in young males. Females may carry the disease but show no vision problems. Further, males with choroideremia cannot pass the disease forward to their children.
As mentioned, the typical initial symptom is night blindness, followed by middle-peripheral vision loss. The central vision seems to be unaffected. Eventually, however, patients exhibit tunnel vision as the disease progresses.
If a patient is diagnosed with choroideremia, he should ask his eye specialist about available clinical trials and other therapeutic options that appear promising.
Although best disease is the commonly used name, this genetic eye disease is actually called vitelliform macular degeneration. Although it’s present from birth, it may not affect vision until much later. The treatment options are experimental, as is the case for choroideremia.
Unlike choroideremia, though, best disease causes central vision difficulties, generally blurriness and distortion. Peripheral vision is generally fine.
If you notice wavy lines in the place of straight lines, this may be a sign of best disease. Later developments may include retinal cystsand cell damage. Even after cysts disappear, they leave behind scarring.
If you suspect vision deterioration, contact your eye professional for a regular eye exam to rule out any of the above genetic eye diseases or start on a course of treatment.