Down syndrome is the common name for a human genetic anomaly, trisomy-21, that arises during the process of meiosis, resulting in a zygote carrying an extra 21st chromosome—three rather than two (hence the name “trisomy”). Down syndrome occurs in one out of every 600 to 800 live births, making it by far the most common form of chromosomal trisomy in the living human population. By comparison, trisomy-18, the next most frequent trisomy in live births, occurs once every 6000 births. In the 19th and 20th centuries, people with Down syndrome were widely considered, by eugenicists, to be among the “unfit.”

From John Langdon Down to Jerome Lejeune
Humans with Down syndrome have existed for at least as long as Homo sapiens and its immediate ancestors, but trisomy-21 was not identified until 1866, when British physician John Langdon Down associated it with phenotypical facial features such as epicanthal folds in the eyelids and flattened noses. Since these features can also be found in certain Asiatic populations, Down syndrome was for many decades referred to as “mongolism.” In fact, Langdon Down’s discovery played a minor part in nineteenth-century debates over the question of evolutionary “polygenesis” – that is, the question of whether humans evolved from different ancestors corresponding to the different human “racial” subgroups (Down himself understood trisomy-21 to be evidence of human monogenesis). The genetic principles behind Down syndrome were not understood for nearly another century. Until 1959, when French physician Jerome Lejeune identified the nondisjunction responsible for the syndrome, conventional wisdom held that Down syndrome was caused at some point in fetal development, and some researchers speculated that fetuses with “mongolism” were “throwbacks” to earlier stages of human evolutionary development.

In an interesting, recent twist to the history of the genetics of Down Syndrome, some have raised the question of the extent to which Lejeune’s discovery was indebted to the work of Marthe Gautier (Fleming 2014), mirroring questions about the discovery of the structure of DNA and the respective roles of James Watson, Francis Crick, and Rosalind Franklin.

Down Syndrome, “Mental Deficiency”, and Eugenics
Between 1866 and 1959, people with Down syndrome were widely considered to be among the “unfit”– incapable of becoming valuable members of society, widely consigned to institutions in which various “idiots,” “imbeciles,” and “morons” were warehoused in often hellish conditions. These terms were not epithets; they were diagnoses, corresponding to various levels of “mental deficiency”. Those with IQs from 51 to 70 were designated as morons, those with IQs from 26 to 50 were imbeciles, and 0 to 25 were idiots. Following the Supreme Court decision of Buck v. Bell (1927), it became permissible to sterilize such people without their consent, the rationale being that they would only do damage to the collective health of the species; as Justice Oliver Wendell Holmes wrote in his (in)famous decision, “three generations of imbeciles are enough.” In The Mismeasure of Man, Stephen Jay Gould revisited the case of the Bell family and suggested credibly that none of the Bell women so designated were in fact “imbeciles.”

People with Down syndrome were therefore (wrongfully) deemed not only incapable of living meaningful lives and having valuable social interactions with their nondisabled peers, but also, and more perniciously, people with Down syndrome were seen as evidence of human degeneration. Over the course of the twentieth-century, conditions in institutions for people with cognitive disabilities deteriorated badly, and the people themselves were considered of such little value that they were fed radioactive oatmeal in the 1950s (as part of an experiment to see how nutrients were absorbed by the body) (“Settlement,” Simon). Not until the shocking exposés of the 1960s and 1970s (e.g., Burton Blatt and Fred Kaplan’s Christmas in Purgatory, Geraldo Rivera’s televised series on Willowbrook in New York) did the conditions of such institutions become the subject of public outrage.

Changing Life Prospects
Down syndrome is associated with mental retardation as well as a wide range of systemic health problems, ranging from congenital heart defects to childhood leukemia to a vastly increased risk of Alzheimer’s Disease in later life. In 1900, the life expectancy for people with Down syndrome was under 10 years, largely because of their increased susceptibility to infection; the discovery of antibiotics helped push the life expectancy beyond 20, and with the advent of open-heart surgery, saving innumerable children who would have died in infancy, the average life expectancy for people with Down syndrome increased to 55. The average quality of life for people with Down syndrome, at least in industrialized nations, has increased more dramatically still. In recent decades, “early intervention” programs for children with Down syndrome have shown that there is a wide spectrum of abilities and disabilities within the category, and that many people with Down syndrome are capable of reading, learning foreign languages, playing musical instruments, and demonstrating other significant capacities for learning and expression. It is no longer uncommon to find adolescents and young adults with Down syndrome graduating from high school, or older persons with Down syndrome working and living independently or in “assisted-living” environments involving other persons with developmental disabilities.

At the same time, however, advances in prenatal fetal screening, combined with a widespread sense in the medical profession that “prevention” through prenatal screening and selective abortion is superior to palliative care, have led many people to see Down syndrome as a human anomaly that is potentially eradicable, and whose eradication would be an unqualified benefit to the species as a whole (Harmon, 2005; Hurley, 2011). Accordingly, advocates for people with Down syndrome– and many people with Down syndrome themselves– have tended to applaud the social advances that have incorporated people with Down syndrome into the fabric of public life while remaining suspicious of new forms of eugenics that threaten to render those social advances moot.

-Michael Berube

• (1998, January 1). Settlement reached in suit over radioactive oatmeal experiment. New York Times. Retrieved from: http://www.nytimes.com/1998/01/01/us/settlement-reached-in-suit-over-radioactive-oatmeal-experiment.html.

• Carlson, E.A. (2001). The unfit: A history of a bad idea. Cold Spring Harbor Laboratory Press.

• Fleming, N. (2014, April 5). J'Accuse. New Scientist, 221(2963), 44-47.

• Gothard, J. (2011). Greater expectations: Living with down syndrome in the 21st century. Fremantle, Western Australia: Fremantle Press.

• Gould, S.J. (1996). The mismeasure of Man. New York: W.W. Norton

• Harmon, A. (2005, November 20). The problem with An almost-perfect genetic world. New York Times. Retrieved from: www.nytimes.com/2005/11/20/weekinreview/20harmon.html?pagewanted=all&_r0

• Hurley, D. (2011, July 29). A drug for down syndrome. New York Times. Retrieved from: http://www.nytimes.com/2011/07/31/magazine/a-fathers-search-for-a-drug-for-down-syndrome.html?pagewanted=all&_r=0

• Simon, B. (2004, April 29). America's deep, dark secret. CBSNews.com. Retrieved from: http://www.cbsnews.com/news/americas-deep-dark-secret/

• Trent, J.W., Jr. (1994). Inventing the Feeble Mind: A history of retardation in the United States. Berkeley, CAP University of California Press

• Wright, D. (2011). Downs: The history of a disability. New York: Oxford University Press.