Down syndrome

Down syndrome encompasses a number of genetic disorders, of which trisomy 21 (a nondisjunction) is the most representative, causing highly variable degrees of learning difficulties as well as physical disabilities. It is named for John Langdon-Down, the British doctor who first described it in the late 19th century.

Overview

Incidence of Down syndrome is estimated at 1 per 660 births, making it the most common chromosomal abnormality. The maternal age effect influences the risk of conceiving a baby with the syndrome. At age 20 to 24, it is 1/1490, while at age 40 it is 1/106, and at age 49 is 1/11. (Source: Hook EB. Rates of chromosomal abnormalities at different maternal ages. Obstet Gynecol 1981;58:282.) Genetic counseling and genetic testing such as amniocentesis are usually offered for families who may be at increased risk to have a child with Down syndrome. Many children with Down syndrome are born to women under the age of 35 because testing is not usually offered to women under the age of 35. Women over 35 are often given an amniocentisis and 9 out of 10 choose to abort the affected fetus.

Related Topics:
Maternal age effect - Genetic counseling - Genetic testing - Amniocentesis

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The term 'Down's syndrome' was first used in 1961 by the editor of The Lancethttp://www.intellectualdisability.info/values/history_DS.htm. It was originally called mongolism or mongolian idiocy, after a perceived resemblance observed by Down between the faces of some of his patients with Down syndrome and the Mongoloid race. This usage is now viewed by medical professionals as offensive and medically meaningless, and is not commonly used today.

Related Topics:
1961 - The Lancet - Mongoloid

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While most children with Down syndrome have a lower than average cognitive function, some have earned college degrees with accommodations, and nearly all will learn to read, write and do simple math. The clinical features of Down syndrome include any of a number of features that also feature in people with a standard set of chromosomes. They include a "simian crease" - a single crease across one or both palms, upslanted eyes, shorter limbs, heart and/or gastroesophageal defects. Young children with Down syndrome are also more prone to recurrent ear infections and obstructive sleep apnea.

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Early educational intervention, screening for common problems such as thyroid functioning, medical treatment where indicated, a conducive family environment, vocational training, etc., can improve the overall development of children with Down syndrome. On the one hand, Down syndrome shows that some genetic limitations can not be overcome; on the other, it shows that education can produce excellent progress whatever the starting point. The commitment of parents, teachers, and therapists to individual children has produced previously unexpected positive results.

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