Table of Contents

    Topic review

    Vitelliform Macular Dystrophy

    View times: 5
    Submitted by: Bruce Ren
    (This entry belongs to Entry Collection "MedlinePlus ")

    Definition

    Vitelliform macular dystrophy is a genetic eye disorder that can cause progressive vision loss. This disorder affects the retina, the specialized light-sensitive tissue that lines the back of the eye. Specifically, vitelliform macular dystrophy disrupts cells in a small area near the center of the retina called the macula. The macula is responsible for sharp central vision, which is needed for detailed tasks such as reading, driving, and recognizing faces.

    Vitelliform macular dystrophy causes a fatty yellow pigment (lipofuscin) to build up in cells underlying the macula. Over time, the abnormal accumulation of this substance can damage cells that are critical for clear central vision. As a result, people with this disorder often lose their central vision, and their eyesight may become blurry or distorted. Vitelliform macular dystrophy typically does not affect side (peripheral) vision or the ability to see at night.

    Researchers have described two forms of vitelliform macular dystrophy with similar features. The early-onset form (known as Best disease) usually appears in childhood; the onset of symptoms and the severity of vision loss vary widely. The adult-onset form begins later, usually in mid-adulthood, and tends to cause vision loss that worsens slowly over time. The two forms of vitelliform macular dystrophy each have characteristic changes in the macula that can be detected during an eye examination.

    1. Introduction

    Vitelliform macular dystrophy causes a fatty yellow pigment (lipofuscin) to build up in cells underlying the macula. Over time, the abnormal accumulation of this substance can damage cells that are critical for clear central vision. As a result, people with this disorder often lose their central vision, and their eyesight may become blurry or distorted. Vitelliform macular dystrophy typically does not affect side (peripheral) vision or the ability to see at night.

    Researchers have described two forms of vitelliform macular dystrophy with similar features. The early-onset form (known as Best disease) usually appears in childhood; the onset of symptoms and the severity of vision loss vary widely. The adult-onset form begins later, usually in mid-adulthood, and tends to cause vision loss that worsens slowly over time. The two forms of vitelliform macular dystrophy each have characteristic changes in the macula that can be detected during an eye examination.

    2. Frequency

    Vitelliform macular dystrophy is a rare disorder; its incidence is unknown.

    3. Causes

    Mutations in the BEST1 and PRPH2 genes cause vitelliform macular dystrophy. BEST1 mutations are responsible for Best disease and for some cases of the adult-onset form of vitelliform macular dystrophy. Changes in the PRPH2 gene can also cause the adult-onset form of vitelliform macular dystrophy; however, less than a quarter of all people with this form of the condition have mutations in the BEST1 or PRPH2 gene. In most cases, the cause of the adult-onset form is unknown.

    The BEST1 gene provides instructions for making a protein called bestrophin. This protein acts as a channel that controls the movement of charged chlorine atoms (chloride ions) into or out of cells in the retina. Mutations in the BEST1 gene probably lead to the production of an abnormally shaped channel that cannot properly regulate the flow of chloride. Researchers have not determined how these malfunctioning channels are related to the buildup of lipofuscin in the macula and progressive vision loss.

    The PRPH2 gene provides instructions for making a protein called peripherin 2. This protein is essential for the normal function of light-sensing (photoreceptor) cells in the retina. Mutations in the PRPH2 gene cause vision loss by disrupting structures in these cells that contain light-sensing pigments. It is unclear why PRPH2 mutations affect only central vision in people with adult-onset vitelliform macular dystrophy.

    4. Inheritance

    Best disease is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person has one parent with the condition.

    The inheritance pattern of adult-onset vitelliform macular dystrophy is uncertain. Some studies have suggested that this disorder may be inherited in an autosomal dominant pattern. It is difficult to be sure, however, because many affected people have no history of the disorder in their family, and only a small number of affected families have been reported.

    5. Other Names for This Condition

    • vitelliform dystrophy

    The entry is from https://medlineplus.gov/genetics/condition/vitelliform-macular-dystrophy

    References

    1. Boon CJ, Klevering BJ, Leroy BP, Hoyng CB, Keunen JE, den Hollander AI. Thespectrum of ocular phenotypes caused by mutations in the BEST1 gene. Prog RetinEye Res. 2009 May;28(3):187-205. doi: 10.1016/j.preteyeres.2009.04.002.
    2. Do P, Ferrucci S. Adult-onset foveomacular vitelliform dystrophy. Optometry.2006 Apr;77(4):156-66.
    3. Felbor U, Schilling H, Weber BH. Adult vitelliform macular dystrophy isfrequently associated with mutations in the peripherin/RDS gene. Hum Mutat.1997;10(4):301-9.
    4. Krämer F, White K, Pauleikhoff D, Gehrig A, Passmore L, Rivera A, Rudolph G,Kellner U, Andrassi M, Lorenz B, Rohrschneider K, Blankenagel A, Jurklies B,Schilling H, Schütt F, Holz FG, Weber BH. Mutations in the VMD2 gene areassociated with juvenile-onset vitelliform macular dystrophy (Best disease) andadult vitelliform macular dystrophy but not age-related macular degeneration. EurJ Hum Genet. 2000 Apr;8(4):286-92.
    5. MacDonald IM, Lee T, Lawrence J. Bestrophinopathies. 2003 Sep 30 [updated 2020Jul 16]. In: Adam MP, Ardinger HH, Pagon RA, Wallace SE, Bean LJH, Stephens K,Amemiya A, editors. GeneReviews® [Internet]. Seattle (WA): University ofWashington, Seattle; 1993-2020. Available fromhttp://www.ncbi.nlm.nih.gov/books/NBK1167/
    6. Renner AB, Tillack H, Kraus H, Kohl S, Wissinger B, Mohr N, Weber BH, Kellner U, Foerster MH. Morphology and functional characteristics in adult vitelliformmacular dystrophy. Retina. 2004 Dec;24(6):929-39.
    7. Renner AB, Tillack H, Kraus H, Krämer F, Mohr N, Weber BH, Foerster MH,Kellner U. Late onset is common in best macular dystrophy associated with VMD2gene mutations. Ophthalmology. 2005 Apr;112(4):586-92.
    8. Seddon JM, Afshari MA, Sharma S, Bernstein PS, Chong S, Hutchinson A,Petrukhin K, Allikmets R. Assessment of mutations in the Best macular dystrophy(VMD2) gene in patients with adult-onset foveomacular vitelliform dystrophy,age-related maculopathy, and bull's-eye maculopathy. Ophthalmology. 2001Nov;108(11):2060-7.
    9. Spaide RF, Noble K, Morgan A, Freund KB. Vitelliform macular dystrophy.Ophthalmology. 2006 Aug;113(8):1392-400.
    10. Wells J, Wroblewski J, Keen J, Inglehearn C, Jubb C, Eckstein A, Jay M, Arden G, Bhattacharya S, Fitzke F, et al. Mutations in the human retinal degenerationslow (RDS) gene can cause either retinitis pigmentosa or macular dystrophy. NatGenet. 1993 Mar;3(3):213-8.
    11. White K, Marquardt A, Weber BH. VMD2 mutations in vitelliform maculardystrophy (Best disease) and other maculopathies. Hum Mutat. 2000;15(4):301-8.Review.
    More
    1. Please check and comment entries here.