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    Topic review

    SOX2 Anophthalmia Syndrome

    Subjects: Genetics
    View times: 5
    Submitted by: Nora Tang
    (This entry belongs to Entry Collection "MedlinePlus ")

    Definition

    SOX2 anophthalmia syndrome is a rare disorder characterized by abnormal development of the eyes and other parts of the body.

    1. Introduction

    People with SOX2 anophthalmia syndrome are usually born without eyeballs (anophthalmia), although some individuals have small eyes (microphthalmia). The term anophthalmia is often used interchangeably with severe microphthalmia because individuals with no visible eyeballs typically have some remaining eye tissue. These eye problems can cause significant vision loss. While both eyes are usually affected in SOX2 anophthalmia syndrome, one eye may be more affected than the other.

    Individuals with SOX2 anophthalmia syndrome may also have seizures, brain abnormalities, slow growth, delayed development of motor skills (such as walking), and mild to severe learning disabilities. Some people with this condition are born with a blocked esophagus (esophageal atresia), which is often accompanied by an abnormal connection between the esophagus and the trachea (tracheoesophageal fistula). Genital abnormalities have been described in affected individuals, especially males. Male genital abnormalities include undescended testes (cryptorchidism) and an unusually small penis (micropenis).

    2. Frequency

    SOX2 anophthalmia syndrome is estimated to affect 1 in 250,000 individuals. About 10 percent to 15 percent of people with anophthalmia in both eyes have SOX2 anophthalmia syndrome.

    3. Causes

    Mutations in the SOX2 gene cause SOX2 anophthalmia syndrome. This gene provides instructions for making a protein that plays a critical role in the formation of many different tissues and organs during embryonic development. The SOX2 protein regulates the activity of other genes, especially those that are important for normal development of the eyes.

    Mutations in the SOX2 gene prevent the production of functional SOX2 protein. The absence of this protein disrupts the activity of genes that are essential for the development of the eyes and other parts of the body. Abnormal development of these structures causes the signs and symptoms of SOX2 anophthalmia syndrome.

    4. Inheritance

    SOX2 anophthalmia syndrome is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Most cases result from new mutations in the SOX2 gene and occur in people with no history of the disorder in their family. In a small number of cases, people with SOX2 anophthalmia syndrome have inherited the altered gene from an unaffected parent who has a SOX2 mutation only in their sperm or egg cells. This phenomenon is called germline mosaicism.

    5.Other Names for This Condition

    • AEG syndrome

    • Anophthalmia-esophageal-genital syndrome

    • SOX2-related eye disorders

    • syndromic microphthalmia 3

    The entry is from https://medlineplus.gov/genetics/condition/sox2-anophthalmia-syndrome

    References

    1. Bakrania P, Robinson DO, Bunyan DJ, Salt A, Martin A, Crolla JA, Wyatt A,Fielder A, Ainsworth J, Moore A, Read S, Uddin J, Laws D, Pascuel-Salcedo D,Ayuso C, Allen L, Collin JR, Ragge NK. SOX2 anophthalmia syndrome: 12 new casesdemonstrating broader phenotype and high frequency of large gene deletions. Br J Ophthalmol. 2007 Nov;91(11):1471-6.
    2. Kelberman D, de Castro SC, Huang S, Crolla JA, Palmer R, Gregory JW, Taylor D,Cavallo L, Faienza MF, Fischetto R, Achermann JC, Martinez-Barbera JP, Rizzoti K,Lovell-Badge R, Robinson IC, Gerrelli D, Dattani MT. SOX2 plays a critical rolein the pituitary, forebrain, and eye during human embryonic development. J ClinEndocrinol Metab. 2008 May;93(5):1865-73. doi: 10.1210/jc.2007-2337.
    3. Schneider A, Bardakjian TM, Zhou J, Hughes N, Keep R, Dorsainville D, Kherani F, Katowitz J, Schimmenti LA, Hummel M, Fitzpatrick DR, Young TL. Familialrecurrence of SOX2 anophthalmia syndrome: phenotypically normal mother with twoaffected daughters. Am J Med Genet A. 2008 Nov 1;146A(21):2794-8. doi:10.1002/ajmg.a.32384.
    4. Tziaferi V, Kelberman D, Dattani MT. The role of SOX2 in hypogonadotropichypogonadism. Sex Dev. 2008;2(4-5):194-9. doi: 10.1159/000152035.
    5. Verma AS, Fitzpatrick DR. Anophthalmia and microphthalmia. Orphanet J RareDis. 2007 Nov 26;2:47. Review.
    6. Williamson KA, Hever AM, Rainger J, Rogers RC, Magee A, Fiedler Z, Keng WT,Sharkey FH, McGill N, Hill CJ, Schneider A, Messina M, Turnpenny PD, Fantes JA,van Heyningen V, FitzPatrick DR. Mutations in SOX2 causeanophthalmia-esophageal-genital (AEG) syndrome. Hum Mol Genet. 2006 May1;15(9):1413-22.15;15(12):2030.
    7. Williamson KA, Yates TM, FitzPatrick DR. SOX2 Disorder. 2006 Feb 23 [updated2020 Jul 30]. 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/NBK1300/
    8. Zhou J, Kherani F, Bardakjian TM, Katowitz J, Hughes N, Schimmenti LA,Schneider A, Young TL. Identification of novel mutations and sequence variants inthe SOX2 and CHX10 genes in patients with anophthalmia/microphthalmia. Mol Vis.2008 Mar 24;14:583-92.
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