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    Down Syndrome

    Important
    It is possible that the main title of the report Down Syndrome is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.

    Synonyms

    • chromosome 21, mosaic Down syndrome
    • chromosome 21, translocation Down syndrome
    • trisomy 21

    Disorder Subdivisions

    • None

    General Discussion

    Down syndrome is a chromosomal condition in which all or a portion of chromosome 21 appears three times (trisomy) rather than twice in cells of the body. In some individuals with this condition, only a percentage of cells may contain the chromosomal condition (mosaicism).

    Symptoms and findings may vary greatly in range and degree, depending on the specific length and location of the duplicated (trisomic) portion of chromosome 21 as well as the percentage of cells containing the condition. However, in many individuals with this condition, such characteristics may include low muscle tone (hypotonia); a tendency to keep the mouth open with protrusion of the tongue; and distinctive facial characteristics including a short, small head (microbrachycephaly), upwardly slanting eyelid folds (palpebral fissures), a depressed nasal bridge, a small nose, and a relatively flat facial profile. Individuals with Down syndrome may also have unusually small, misshapen (dysplastic) ears; a narrow roof of the mouth (palate); vertical skin folds covering the inner corners of the eyes (epicanthal folds); dental abnormalities; and excessive skin on the back of the neck. Other characteristics include unusually short arms and legs; short fingers; and unusual skin ridge patterns (dermatoglyphics) on the fingers, palms, and toes. Individuals with Down syndrome may also have short stature, poor coordination, mild to severe intellectual disability, and hearing impairment.

    In some cases, Down syndrome may also be characterized by structural malformations of the heart at birth (congenital heart defects). In addition, those with the condition may have an increased susceptibility to respiratory disease (e.g., pneumonia), other infectious diseases, and malignancies in which there is an increased proliferation of certain white blood cells (leukemia). Rarely do these conditions lead to potentially life-threatening complications.

    Resources

    March of Dimes Birth Defects Foundation
    1275 Mamaroneck Avenue
    White Plains, NY 10605
    Tel: (914)997-4488
    Fax: (914)997-4763
    Tel: (888)663-4637
    Email: Askus@marchofdimes.com
    Internet: http://www.marchofdimes.com

    The Arc
    1825 K Street NW, Suite 1200
    Washington, DC 20006
    Tel: (202)534-3700
    Fax: (202)534-3731
    Tel: (800)433-5255
    TDD: (817)277-0553
    Email: info@thearc.org
    Internet: http://www.thearc.org

    National Down Syndrome Congress
    30 Mansell Ct
    Suite 108
    Roswell, GA 30076
    USA
    Tel: (770)604-9500
    Fax: (770)604-9898
    Tel: (800)232-6372
    Email: info@ndsccenter.org
    Internet: http://www.ndsccenter.org

    National Down Syndrome Society
    666 Broadway
    8th Floor
    New York, NY 10012-2317
    USA
    Fax: (212)979-2873
    Tel: (800)221-4602
    Email: info@ndss.org
    Internet: http://www.ndss.org/

    PHP - Parents Helping Parents, Inc.
    Sobrato Center For Nonprofits San Jose
    1400 Parkmoor Avenue,
    Suite 100
    Santa Clara, CA 95126
    USA
    Tel: (408)727-5775
    Fax: (408)286-1116
    Tel: (866)747-4040
    Email: info@php.com
    Internet: http://www.php.com

    Association for Children with Down Syndrome, Inc.
    4 Fern Place
    Plainview, NY 11803
    Tel: (516)933-4700
    Fax: (516)933-9524
    Email: msmith@acds.org
    Internet: http://www.acds.org

    NIH/National Institute of Child Health and Human Development
    31 Center Dr
    Building 31, Room 2A32
    MSC2425
    Bethesda, MD 20892
    Fax: (866)760-5947
    Tel: (800)370-2943
    TDD: (888)320-6942
    Email: NICHDInformationResourceCenter@mail.nih.gov
    Internet: http://www.nichd.nih.gov/

    Birth Defect Research for Children, Inc.
    976 Lake Baldwin Lane
    Orlando, FL 32814
    USA
    Tel: (407)895-0802
    Email: staff@birthdefects.org
    Internet: http://www.birthdefects.org

    International Mosaic Down Syndrome Association
    PO Box 1052
    Franklin, TX 77856
    Tel: (979)828-4177
    Fax: (775)295-9373
    Tel: (888)637-5465
    Email: president@imdsa.org
    Internet: http://www.imdsa.org/

    R.O.C.K. (Raising Our Celiac Kids)
    3527 Fortuna Ranch Rd
    Encinitas, CA 92024
    USA
    Tel: (858)395-5421
    Fax: (858)756-0431
    Email: info@celiackids.com
    Internet: http://www.celiackids.com

    New Horizons Un-Limited, Inc.
    811 East Wisconsin Ave
    P.O. Box 510034
    Milwaukee, WI 53203
    USA
    Tel: (414)299-0124
    Fax: (414)347-1977
    Email: horizons@new-horizons.org
    Internet: http://www.new-horizons.org

    Genetic and Rare Diseases (GARD) Information Center
    PO Box 8126
    Gaithersburg, MD 20898-8126
    Tel: (301)251-4925
    Fax: (301)251-4911
    Tel: (888)205-2311
    TDD: (888)205-3223
    Internet: http://rarediseases.info.nih.gov/GARD/

    Madisons Foundation
    PO Box 241956
    Los Angeles, CA 90024
    Tel: (310)264-0826
    Fax: (310)264-4766
    Email: getinfo@madisonsfoundation.org
    Internet: http://www.madisonsfoundation.org

    ANDO (Apoyo al Nino Down)
    Dept. of Medical Genetics, Children's National Medical Center
    111 Michigan Avenue
    Suite 1950
    Washington, DC 20010
    Tel: (202)476-5793
    Fax: (202)476-2390
    Email: curuburo@cnmc.org

    National Foundation for Celiac Awareness
    P.O. Box 544
    224 South Maple Street
    Ambler, PA 19002
    Tel: (215)325-1306
    Fax: (215)643-1707
    Email: info@celiaccentral.org
    Internet: http://www.CeliacCentral.org

    Perkins School for the Blind
    175 North Beacon Street
    Watertown, MA 02472
    Tel: (617)924-3434
    Fax: (617)926-2027
    Email: Info@Perkins.org
    Internet: http://www.Perkins.org

    National Consortium on Deaf-Blindness
    The Teaching Research Institute
    345 N. Monmouth Avenue
    Monmouth, OR 97361
    Tel: (800)438-9376
    Fax: (503)838-8150
    Tel: (800)438-9376
    TDD: (800)854-7013
    Email: info@nationaldb.org
    Internet: http://www.nationaldb.org

    PLAN Institute for Caring Citizenship
    Suite 260 - 3665 Kingsway
    Vancouver
    British Columbia, V5R 5W2
    Canada
    Tel: 6044399566
    Fax: 6044397001
    Email: inquiries@planinstitute.ca
    Internet: http://www.planinstitute.ca/?q=learnfromus/library

    Child Neurology Foundation
    201 Chicago Ave, #200
    Minneapolis, MN 55415
    USA
    Tel: (952)641-6100
    Fax: (952)881-6276
    Tel: (877)263-5430
    Email: jstone@childneurologyfoundation.org
    Internet: http://www.childneurologyfoundation.org

    Medical Home Portal
    Dept. of Pediatrics
    University of Utah
    P.O. Box 581289
    Salt Lake City, UT 84158
    Tel: (801)587-9978
    Fax: (801)581-3899
    Email: mindy.tueller@utah.edu
    Internet: http://www.medicalhomeportal.org

    For a Complete Report:

    This is an abstract of a report from the National Organization for Rare Disorders (NORD). A copy of the complete report can be downloaded free from the NORD website for registered users. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational therapies (if available), and references from medical literature. For a full-text version of this topic, go to www.rarediseases.org and click on Rare Disease Database under "Rare Disease Information".

    The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.

    It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report

    This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

    For additional information and assistance about rare disorders, please contact the National Organization for Rare Disorders at P.O. Box 1968, Danbury, CT 06813-1968; phone (203) 744-0100; web site www.rarediseases.org or email orphan@rarediseases.org

    Last Updated: 4/9/2012
    Copyright 1984, 1985, 1987, 1988, 1990, 1992, 1996, 1997, 1998, 1999, 2000, 2002, 2003, 2008, 2012 National Organization for Rare Disorders, Inc.

    WebMD Medical Reference from the National Organization for Rare Disorders

    Last Updated: May 28, 2015
    This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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