Best vitelliform macular dystrophy is an autosomal dominant genetic form of macular degeneration that usually begins in childhood or adolescence and slowly progresses to affect central vision. The age of onset and severity of vision loss are highly variable. Best vitelliform macular dystrophy is associated with an abnormality in the VMD2 gene.

BVMD has an average age of onset between age 5 and 10 but can vary from person to person. Affected individuals initially have normal vision and then experience blurred vision, reduced sharpness or clarity of vision or the appearance of objects that have a distorted shape (metamorphosia). BVMD affects central vision but usually not peripheral vision and varies in severity.

Some people with the disorder do not notice a decline in vision and may be diagnosed in passing from a routine eye exam. Others experience significant loss of vision, which can occur because of the formation of blood vessels under the macula and retina (choroidal neovascularization). The degree of visual loss can be different in each eye. Most individuals with BVMD have one eye more severely affected than the other and can continue to perform daily tasks such as driving well into the later decades of life.

The macula is the region of the retina that contains the light-sensing cells necessary for central vision. Individuals with BVMD develop a yellowish material under the macula that resembles an egg yolk (vitelliform means yolk-like). This material eventually breaks up and spreads throughout the macula, leading to a reduction in central vision. Lipofuscin, a chemical made by the body, makes up this yolk-like material.

BVMD is inherited as an autosomal dominant genetic condition and is usually associated with the mutations in the BEST1 gene. Dominant genetic disorders occur when only a single copy of a non-working gene is necessary to cause a particular disease. The non-working gene can be inherited from either parent. It can also occur as a new gene change in the affected individual. Most individuals affected with BVMD have an affected parent. The chance of passing the abnormal gene from an affected parent to an offspring is 50% for each pregnancy. The risk is the same for males and females.

When working normally, the BEST1 gene acts as a gate to help move chemicals between cells in the retina. When this “gate” isn’t working properly, this can cause the build up of fluid and lipofuscin in the retinal tissue. Because BVMD is a progressive condition, there are different stages that are recognized.

• vitelliform stage (stage 1): The stage most commonly seen in new diagnoses of BVMD. In this stage, the macula has the characteristic pocket of yellow-material that can be seen upon examination.
• pseudohypopyon stage (stage 2): The pocket of yellow material moves towards the bottom of the eye. This creates fluid layers where the bottom is the yellow yolk-like fluid and the top is a clear fluid.
• vitelliruptive stage (last stage): The common fluid layers become more spread out in the retina tissue. This spreading can lead to the formation of blood vessels under the macula (choroidal neovascularization) and can significantly impair central vision.

The BEST1 gene is one of two genes associated with this condition. This gene is linked to the early onset form of this condition typically presenting in late childhood or early adolescence. BVMD-like symptoms diagnosed after age 20 with no gene abnormality in the BEST1 gene may be associated with mutations in the PRPH2 gene which is linked to adult-onset BVMD.

There is no cure for BVMD but there are treatment options available that can help reduce the effects of vision loss. For individuals with BVMD who have choroidal neovascularization, anti-VEGF therapy is available to help limit the formation of blood vessels in the macula.

Affected individuals should have regular eye examinations to monitor the progression of the disease. Devices or aids to help with poor vision are beneficial for those who experience significant vision loss.

If the eye lesions are large enough, sudden injury to the eye or head may lead to bursting of the lesions. People with BVMD should avoid strenuous exercise or high contact activity that may lead to head trauma.

Genetic counseling is beneficial for affected individuals and their families. These specialists can provide information on the genetic causes of certain inherited conditions, counsel on the chance of genetic disease reoccurring in the family, discuss the availability of different genetic testing options, and provide resources related to genetic disease.

BVMD is fairly common form of macular degeneration affecting about 1 in 10,000 individuals. Typical age of onset is between the ages of 5 and 10 but can occur earlier or later. BVMD occurs equally often in men and women. This condition has been diagnosed in individuals of European, African and Hispanic ancestry.

Treatment of vitelliform macular dystrophy

A vieltfimorm macular dystrophy is a genetic form of macular degeneration. It is when the part of the eye called the macula is damaged. The physical cause of the breakdown of the retinal pigment epithelium. It starts with blurred central vision and gets worse with complete loss of vision. But the peripheral vision and ability of the eye to adjust to dark status are unaffected. The age that it starts to show symptoms usually varies. But it can start from early childhood to adulthood.

1. There is no treatment for this but there are some treatments or therapies that can help reduce the effect of vision loss. The individual who has choroidal neovascularization, anti-VEGF therapy, helps to limit the formation of blood cells in the macula.

2. One affected should make sure to get eye check ups regularly to get an update on the progression of the disease.

3. Strenuous exercise or high-contact activity that might lead to head trauma should be something one with large lesions be careful of as it might lead to the bursting of lesions.

4. Individuals with the disease might get genetic testing for themselves and their families to get to know if the disease is running in the family and what resources can be used or help to take precautions for the recurring case of the disease in the family.

Symptoms
Blurred vision,Reduced sharpness or clarity of vision or the appearance of objects that have a distorted shape (metamorphopsia)
Conditions
Worsening (progressive) vision loss
Drugs
NA