National Organization for Rare Disorders, Inc.
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.
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.
March of Dimes Birth Defects Foundation
1275 Mamaroneck Avenue
White Plains, NY 10605
1825 K Street NW, Suite 1200
Washington, DC 20006
National Down Syndrome Congress
30 Mansell Ct
Roswell, GA 30076
National Down Syndrome Society
New York, NY 10012-2317
PHP - Parents Helping Parents, Inc.
Sobrato Center For Nonprofits San Jose
1400 Parkmoor Avenue,
Santa Clara, CA 95126
Association for Children with Down Syndrome, Inc.
4 Fern Place
Plainview, NY 11803
NIH/National Institute of Child Health and Human Development
31 Center Dr
Building 31, Room 2A32
Bethesda, MD 20892
Birth Defect Research for Children, Inc.
976 Lake Baldwin Lane
Orlando, FL 32814
International Mosaic Down Syndrome Association
PO Box 1052
Franklin, TX 77856
R.O.C.K. (Raising Our Celiac Kids)
3527 Fortuna Ranch Rd
Encinitas, CA 92024
New Horizons Un-Limited, Inc.
811 East Wisconsin Ave
P.O. Box 510034
Milwaukee, WI 53203
Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
PO Box 241956
Los Angeles, CA 90024
ANDO (Apoyo al Nino Down)
Dept. of Medical Genetics, Children's National Medical Center
111 Michigan Avenue
Washington, DC 20010
National Foundation for Celiac Awareness
P.O. Box 544
224 South Maple Street
Ambler, PA 19002
Perkins School for the Blind
175 North Beacon Street
Watertown, MA 02472
National Consortium on Deaf-Blindness
The Teaching Research Institute
345 N. Monmouth Avenue
Monmouth, OR 97361
PLAN Institute for Caring Citizenship
Suite 260 - 3665 Kingsway
British Columbia, V5R 5W2
Child Neurology Foundation
2000 West 98th Street
Bloomington, MN 55431
Medical Home Portal
Dept. of Pediatrics
University of Utah
P.O. Box 581289
Salt Lake City, UT 84158
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 firstname.lastname@example.org
Last Updated: 4/9/2012
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