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Down Syndrome

National Organization for Rare Disorders, Inc.

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.

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