Down Syndrome

Down syndrome, congenital disorder characterized by mild to severe mental retardation, slow physical development, and characteristic physical features. Down syndrome affects about 1 in every 730 live births and occurs in all populations equally. It was first described in 1866 by an English physician, J. Langdon Down. In 1959 a French physician, Jerome Lejeune, discovered that the syndrome was caused by an extra chromosome. It was later discovered that this extra chromosome appears as a third chromosome attached to the 21st of the 23 pairs of chromosomes normally present in the human genome. This third chromosome gives rise to the alternate name trisomy 21.

The extra genetic material is responsible for the physical characteristics of the syndrome: low muscle tone, flattish facial features, an upward slant to the eyes and epicanthal folds (which were the basis for the former name, mongolism), a single crease across the palm, hyperflexibility of the joints, and a displastic middle phalanx on the fifth finger. People with Down syndrome have an increased incidence of infection, childhood leukemia, congenital heart defects, and respiratory problems, but modern medical treatment has improved the life expectancy from 9 (in 1910) to 55 (in 1995).

Mental retardation varies widely, from minimal to severe. The great majority of those who have the disorder attend public schools and as adults can live independently or in group homes. After age 35 individuals with the syndrome develop the neurological changes of Alzheimer's disease, and many develop the dementia that accompanies them.

Eighty percent of children with Down syndrome are born to women under 35 years of age, but the incidence of Down syndrome births does increase with age. Approximately 5% of cases are transmitted by the sperm. Amniocentesis or chorionic villus sampling can be used to detect the disorder in the fetus. Children born to women with Down syndrome have a 50% chance of having the disorder.

The Columbia Encyclopedia, 6th ed. Copyright© 2018, The Columbia University Press.

Down Syndrome: Selected full-text books and articles

Of Mice & Men: Advancements in the Understanding of Down Syndrome By Silverman, Wayne The Exceptional Parent, Vol. 37, No. 7, July 2007
Parents, Advocates Want to Eradicate Down Syndrome Stigma By Schlumpf, Heidi National Catholic Reporter, Vol. 54, No. 7, January 12, 2018
Down Syndrome Debates By Jamie Edgin; Fabian Fernandez International New York Times, August 30, 2014
Testing Times: DOWN SYNDROME AND THE NEW ABORTION BATTLEGROUND By Fisher, Jane Conscience, Vol. 39, No. 2, Summer 2018
Parenting Satisfaction and Self-Efficacy: A Longitudinal Study of Mothers of Children with Down Syndrome By Gilmore, Linda; Cuskelly, Monica Journal of Family Studies, Vol. 18, No. 1, June 2012
PEER-REVIEWED PERIODICAL
Peer-reviewed publications on Questia are publications containing articles which were subject to evaluation for accuracy and substance by professional peers of the article's author(s).
Psychological Well-Being in Fathers of Adolescents and Young Adults with Down Syndrome, Fragile X Syndrome, and Autism By Hartley, Sigan L.; Seltzer, Marsha Mailick; Head, Lara; Abbeduto, Leonard Family Relations, Vol. 61, No. 2, April 2012
PEER-REVIEWED PERIODICAL
Peer-reviewed publications on Questia are publications containing articles which were subject to evaluation for accuracy and substance by professional peers of the article's author(s).
What General Educators Have to Say about Successfully Including Students with Down Syndrome in Their Classes By Wolpert, Gloria Journal of Research in Childhood Education, Vol. 16, No. 1, Fall-Winter 2001
PEER-REVIEWED PERIODICAL
Peer-reviewed publications on Questia are publications containing articles which were subject to evaluation for accuracy and substance by professional peers of the article's author(s).
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