What is Down Syndrome?
Down syndrome is a genetic disorder that is present from birth. It is caused by an extra chromosome that develops called chromosome 21 and is often referred to as trisomy 21. The condition was recognised in 1866 by Langdon Down, who detailed the first systematic description (Burns & Gunn, 1993). However it was not until 1959 that Professor Jerome Lejeune identified the characteristic of the extra chromosome, which led to a positive diagnosis of the genetic disorder (Burns & Gunn, 1993). Down syndrome is the most common form of a learning disability and the most common chromosomal condition affecting newborn babies. Due to the presence of the extra chromosome, it causes various intellectual and physical characteristics that define it as Down syndrome.
What are the Causes and How Common is it?
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The extra copy of chromosome 21 comes from either the sperm or egg, however as women get older, the chance of having a child with Down syndrome increases dramatically.
“Down syndrome increases with maternal age, at ages less than 30 years for the mother, incidence is less than one in 1000. This rises to one in 400 at age 35, and up to one in 12 by age 49 years.” (Vize, 2011, p34). Although there are no known causes of the extra chromosome occurring, the chances are increased for women over 35 years.
“Down syndrome increases with maternal age, at ages less than 30 years for the mother, incidence is less than one in 1000. This rises to one in 400 at age 35, and up to one in 12 by age 49 years.” (Vize, 2011, p34). Although there are no known causes of the extra chromosome occurring, the chances are increased for women over 35 years.
Image references
Image retrieved on May 5, 2013 from How to Pick a School for a Down Syndrome Child
Image retrieved on May 5, 2013 from Special Ed Post
Image retrieved on May 5, 2013, from EDUC220 Spring 2010
Image retrieved on May 5, 2013 from How to Pick a School for a Down Syndrome Child
Image retrieved on May 5, 2013 from Special Ed Post
Image retrieved on May 5, 2013, from EDUC220 Spring 2010