Down syndrome in lay language

Down syndrome, also known as Trisomy 21, is a naturally occurring condition in which a person has three copies of the 21st chromosome rather than two copies. It is the most commonly occurring genetic mutation, and the one most frequently diagnosed prenatally. It has no known cause. Although medical research is proceeding, no treatments have yet been developed to improve cognition in people with DS. It is estimated that 350,000 Americans have Down syndrome. In the United States, between 85 and 90 percent of prenatally diagnosed cases of Down syndrome end in abortion.

People with Down syndrome have historically faced discrimination and exclusion, and were regularly institutionalized, imprisoned and involuntarily sterilized well into the 20th century. Until the 1970s, they were routinely denied access to education. They still lack appropriate health care and housing in many cases.

Educational access is now protected by law, and as a consequence people with Down syndrome are increasingly completing high school, embarking on post-secondary study, and living and working semi-independently. Many of the characteristics that were once thought to be endemic to Down syndrome now seem to have been caused by institutionalization and social ostracism.

All of them have unique personalities and interests, as their family members can tell you. Recent studies report that families of people with Down syndrome are affected more positively than negatively. Waiting lists of families wishing to adopt children with Down syndrome are now being reported. (See Lindh, Heidi L., et al., "Characteristics and perspectives of families waiting to adopt a child with Down Syndrome," Genetics in Medicine, April, 2007.)

Down syndrome is characterized by developmental delays that are most often mild to moderate, but occasionally can be more severe. It is impossible to predict the extent of these delays based on prenatal diagnosis or observation of other physical symptoms. People with Down syndrome are at a heightened risk of heart problems, most of them surgically correctible, as well as early onset Alzheimer’s disease and leukemia. They often have recognizable facial characteristics, most notably the epicanthal fold of the upper eyelid that is also common in people of Asian descent.

Historically, the condition now known as Down syndrome was wrongly believed to be a racial degeneration, perhaps caused by disease or alcoholism in the mother. In Victorian England the disorder was labeled “mongolism” by doctor John Langdon Down, reflecting the popular Victorian belief that Mongolians were a lower form of human.

The genetic basis of the condition was discovered by Dr. Jerome Lejeune in Paris in 1959. Dr. Lejeune campaigned unsuccessfully against the use of his discovery for the purpose of prenatal screening and abortion, and called for ongoing scientific research into possible treatments for people with DS. In the years since, prenatal screening and abortion have flourished, while funding for research to treat the cognitive symptoms of people with DS has been meager.

In the 1960s, the British medical journal the Lancet recommended that the name “mongolism” be dropped after receiving a letter from leading geneticists charging that the name was “misleading” and had ”embarrassing” connotations. Subsequently, the World Health Organization dropped references to the term “mongolism” after receiving a complaint from a Mongolian delegate.

While considered offensive, the term is still in use among some medical professionals and appears in some medical texts as well as in the online prenatal guide of Harvard's Brigham and Women's Hospital. “Down syndrome” is the accepted term among professionals in the United States. In France, it is called "Trisomy 21."