Down Syndrome: Background information when reading The Shock of The Fall

Down Syndrome

This article relates to The Shock of The Fall

In Where The Moon Isn't, the protagonist's brother, Simon Homes, has Down syndrome.

Down syndrome is the most common genetic abnormality being present in one of every 691 births in the United States. All humans have 23 pairs of chromosomes. Down's is caused when the 21st set has a partial or a whole extra copy, which means that there are three copies of the 21st chromosome (trisomy). Trisomies can occur with other pairs of chromosomes as well, giving rise to different disorders, but Down's is defined as the one affecting the 21st pair only. This error in cell division happens at conception and its causes are still unknown.

Down's manifests itself with a particular set of facial characteristics including flattened profile and slight upward slant to the eyes. There is a greater chance of heart problems with Down's and babies are usually screened immediately to identify these. Individuals with Down's usually have a higher rate of thyroid and respiratory infections as well. Most have mild to moderate intellectual disability although with special education, adults can hold jobs in well-supervised atmospheres.

The syndrome, which is named after the British physician, John Langdon Down who described the condition in 1866, can be detected by means of neonatal tests including more invasive ones such as amniocentesis.

In 2013, U.S. researchers reported finding a technique that would disable the extra copy of the 21st chromosome from being expressed, in effect suppressing the cells that cause Down's. An RNA gene called Xist was spliced into lab-grown stem cells with Down's. The result was that Xist modified the extra copy so as to deactivate most of its genes and the protein production associated with Down's. Scientists hope that this method will help further research into Down's and its treatment, although they caution that it's still too early in the research stage to be successfully carried through.

Picture of Down syndrome trisomy from National Human Genome Research Institute

Filed under Medicine, Science and Tech

This "beyond the book article" relates to The Shock of The Fall. It originally ran in January 2014 and has been updated for the October 2014 paperback edition. Go to magazine.