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Disease Profile

Best vitelliform macular dystrophy

Prevalence
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

Unknown

Age of onset

Childhood

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ICD-10

H35.5

Inheritance

Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease

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Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype

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X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

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X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder

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Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.

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Not applicable

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Other names (AKA)

Best disease; Best macular dystrophy; Macular degeneration, polymorphic vitelline;

Categories

Congenital and Genetic Diseases; Eye diseases

Summary

Best vitelliform macular dystrophy (BVMD) is a slowly progressive form of macular degeneration. It usually begins in childhood or adolescence, but age of onset and severity of vision loss can vary. Affected people first have normal vision, followed by decreased central visual acuity and distorted vision (metamorphopsia). Peripheral vision is not affected.[1] BVMD is characterized by atrophy of the retinal pigment epithelium (The retina is the back part of the eye that contains the specialized cells that respond to light, known as photoreceptors) and impaired central visual function.[2] BVMD is usually inherited in an autosomal dominant manner, but autosomal recessive inheritance has been reported. The condition is typically caused by mutations in the BEST1 gene; in a few cases the cause is unknown. Treatment is symptomatic and involves the use of low vision aids, and direct laser treatment or photodynamic therapy. Newer treatment includes anti-VEGF agents (bevacizumab) and transcorneal electrical retinal stimulation.[1]

Symptoms

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Cystoid macular degeneration
0008028
Metamorphopsia
0012508
30%-79% of people have these symptoms
Color vision defect
Abnormal color vision
Abnormality of color vision

[ more ]

0000551
5%-29% of people have these symptoms
Choroideremia
0001139
Visual field defect
Partial loss of field of vision
0001123
Percent of people who have these symptoms is not available through HPO
Abnormal electroretinogram
0000512
Autosomal dominant inheritance
0000006
Macular dystrophy
0007754
Reduced visual acuity
Decreased clarity of vision
0007663
Subretinal fluid
0031526
Visual impairment
Impaired vision
Loss of eyesight
Poor vision

[ more ]

0000505

Cause

Best vitelliform macular dystrophy (BVMD) is caused by changes (mutations) in the BEST1 gene.[1] This gene gives the body instructions for making a protein called bestrophin. Bestrophin acts as a channel that controls the movement of chloride ions within the retina. It is thought that mutations in the BEST1 gene affect the shape of the channel and its ability to properly regulate the flow of chloride. However, it is unclear how exactly this relates to the specific features of BVMD.[3]

Diagnosis

Best vitelliform macular dystrophy (BVMD) may be diagnosed based on the findings on an exam of the fundus (the interior surface of the eye opposite the lens); an electrooculogram (EOG); and the family history. An eye exam may include other tests as well. A fundus exam may show a typical yellow yolk-like macular lesion.

The EOG, which reflects the retinal pigmentary epithelium function, is the most diagnostic test for evaluating vitelliform macular dystrophy. In the majority of the cases, a severe decrease occurs in light response, reflected by an Arden (light-peak/dark-trough) ratio of 1.1-1.5. (The normal Arden ratio is 1.8.) Carriers will also have an abnormal EOG result. No correlation exists between EOG result and disease stage, visual acuity, or patient age. EOG results are usually symmetric for both eyes.[4]

The family history in affected people is often consistent with either autosomal dominant or autosomal recessive inheritance.[1]

Genetic testing may also be used to make a diagnosis of BVMD. A BEST1 mutation is detected in about 96% of affected people who have an affected family member. In people with no family history of BVMD, the mutation detection rate ranges between 50-70%. A mutation in BEST1 gene is more probable when a vitelliform lesion is accompanied by a reduced Arden ratio on EOG testing. The exact type of genetic test ordered to confirm a diagnosis may depend on a person's ancestry, family history, and/or whether other eye disorders are also being considered.[1]

Treatment

There is no specific treatment for Best vitelliform macular dystrophy (BVMD) at this time.[5][4] Low vision aids help affected people with significant loss of visual acuity.[6] Laser photocoagulation, photodynamic therapy, and anti-VEGF (vascular endothelial growth factor) agents such as bevacizumab have shown limited success in treating some of the secondary features of BVMD such as choroidal neovascularization (when abnormal blood vessels grow under the macula and retina).[6][5][4]

Organizations

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

    Social Networking Websites

      Organizations Providing General Support

        Learn more

        These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

        Where to Start

        • MedlinePlus Genetics contains information on Best vitelliform macular dystrophy. This website is maintained by the National Library of Medicine.
        • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

          In-Depth Information

          • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
          • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
          • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
          • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
          • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
          • PubMed is a searchable database of medical literature and lists journal articles that discuss Best vitelliform macular dystrophy. Click on the link to view a sample search on this topic.

            References

            1. MacDonald IM & Lee T. Best Vitelliform Macular Dystrophy. GeneReviews. December 12, 2013; https://www.ncbi.nlm.nih.gov/books/NBK1167/.
            2. Ian MacDonald. Best vitelliform macular dystrophy. Orphanet. December, 2013; https://www.orpha.net/consor4.01/www/cgi-bin/OC_Exp.php?lng=EN&Expert=1243.
            3. Vitelliform macular dystrophy. Genetics Home Reference. December, 2013; https://ghr.nlm.nih.gov/condition/vitelliform-macular-dystrophy.
            4. Altaweel M. Best Disease. Medscape Reference. 2016; https://emedicine.medscape.com/article/1227128.
            5. Besch D, Zrenner E. Best disease. Orphanet. 2013; https://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=EN&Expert=1243.
            6. MacDonald IM, Lee T. Best Vitelliform Macular Dystrophy. GeneReviews. 2013; https://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=bvd.

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