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Trisomy 21, known as Down syndrome, is a genetic disorder resulting from genetic errors on the 21st chromosome. Down syndrome causes a range of intellectual impairments and developmental delays as well as health conditions.
Down syndrome is the most common Trisomy. Although most trisomies are due to random errors, mothers over 35 years of age have an increased risk of having a child with Down syndrome. Down syndrome occurs in approximately 1 in 700 live births, or about 6,000 babies every year.
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About Down Syndrome
Impact on Development
Some children will have three copies of chromosome 21 in all of their cells (Trisomy 21) while others have three copies in only some of their cells (mosaic Down syndrome) or extra parts of chromosome 21 attached to another chromosome (Translocation Down syndrome). The severity of the impact of Trisomy 21 on development will depend upon the number of cells affected.
Children with Down syndrome have distinctive facial features such as a flattened face, a short neck, almond-shaped eyes, and a small mouth with a tongue that appears to stick out. Most will have mild to moderate developmental and intellectual disabilities, although children with Down syndrome will vary considerably in their abilities.
Trisomy 21 is also associated with other health problems. Children with Down syndrome are at an increased risk for having heart defects, digestive problems such as gastroesophageal reflux or celiac disease, and hearing and vision problems. They may also have problems with their thyroid and have increased risk for leukemia or infections.
Clinical Course and Life Expectancy
Children with Down syndrome often have low muscle tone at birth and may experience life-threatening medical conditions, such as those associated with heart defects. Unlike other Trisomy disorders, most children with Down syndrome will live into adulthood. Individuals with Down syndrome with fewer or well-managed health problems can expect to live to be 60 years of age or more.
For More Information
There is no cure for Down syndrome; however, most individuals can live happy, productive lives. Medical conditions such as heart defects may require surgical correction or management with medication. Therapeutic services, such as speech, occupational, and physical therapy, should be provided as soon as possible to children with Down syndrome to assist their development. Early Intervention services received in infancy will ensure that families have the support needed to promote their child’s development and health and improve their physical and intellectual abilities.
Down Syndrome Resources
Resources for Families
- The National Down Syndrome Congress (NDSC)
The NDSC is committed to building a sense of community among all those concerned with Down syndrome. The National Down Syndrome Congress offers information on any subject related to Down syndrome. It also maintains a directory to promote parent-to-parent and parent-to-professional networking.
Call 1-800-232-6372 for more information.
- Down Syndrome Diagnosis Network connects, supports, and provides accurate information to parents and medical professionals.
- The Arc of Mississippi is a grassroots advocacy organization for citizens of all ages with cognitive, intellectual and developmental disabilities, and their families. The Arc promotes the welfare and full inclusion of individuals with intellectual and developmental disabilities and provides family support and advocacy.
- Mississippi Society for Disabilities supports the needs of Mississippi's disabled/special needs community through innovative approaches.
- The Mississippi Division of Medicaid provides access to health coverage for children with disabilities
Resource Centers or Clearinghouses
- Down Syndrome Resource Foundation (DSRF) offers educational and health opportunities to children and young adults with Down syndrome. Their programs are based on the latest intervention research and best practice and adapted for individual learner's needs.
National and Local Organizations
Education and Support Programs
Resources for Healthcare Providers
- American Academy of Pediatrics. Bull MJ and the Committee on Genetics. Health Supervision for Children With Down Syndrome. Pediatrics 2011;128;393; DOI: 10.1542/peds.2011-1605;
- Dalrymple RA, Somerville LH, Hamza S, Matta N. Fifteen-minute consultation: The review of a child with trisomy 21 (Down's syndrome). Arch Dis Child Educ Pract Ed. 2021 Jan 15:edpract-2020-319814. doi: 10.1136/archdischild-2020-319814. Epub ahead of print. PMID: 33452013
- Glinianaia SV, Morris JK, Best KE, Santoro M, Coi A, Armaroli A, et al. (2020) Long-term survival of children born with congenital anomalies: A systematic review and meta-analysis of population-based studies. PLoS Med 17(9): e1003356.
- Kirby RS. The prevalence of selected major birth defects in the United States. Semin Perinatol. 2017 Oct;41(6):338-344. doi: 10.1053/j.semperi.2017.07.004. PMID: 29037343.
- Lantin-Hermoso MR, Berger S, Bhatt AB, Richerson JE, Morrow R, Freed MD, Beekman RH. The Care of Children with Congenital Heart Disease in Their Primary Medical Home. Pediatrics 2017;140(5);e20172607;
- Lee CF, Lee CH, Hsueh WY, Lin MT, Kang KT. Prevalence of obstructive sleep apnea in children with Down syndrome: a meta-analysis. J Clin Sleep Med. 2018;14(5):867–875;
- Lipkin, P.H., Okamoto, J., and the Council on Children with Disabilities and the Council on School Health. The Individuals With Disabilities Education Act (IDEA) for Children With Special Educational Needs. Pediatrics 2015;136;e1650. DOI: 10.1542/peds.2015-3409;
- Santoro JD, Pagarkar D, Chu DT, Rosso M, Paulsen KC, Levitt P, Rafii MS. Neurologic complications of Down syndrome: a systematic review. J Neurol. 2020 Sep 12. doi: 10.1007/s00415-020-10179-w. Epub ahead of print. PMID: 32920658.
Last reviewed on Mar 23, 2023