Edwards syndrome is caused by an autosomal trisomy of chromosome 18, hence it is otherwise known as Trisomy 18. A trisomy is where an individual develops 3 copies of a chromosome instead of two. This usually happens randomly during the formation of gametes, so can occur either in the egg or the sperm. As this occurs randomly, it is very unlikely for a woman to have more than one child affected by Edwards syndrome. Edwards syndrome can cause mental retardation and malformation of the heart.
Nearly three-quarters of babies with this trisomy are either miscarried or still born. Another example of a disease or syndrome caused by an autosomal trisomy is Down Syndrome, however in this instance the trisomy occurs on chromosome 21.
- ↑ Pasternak, J J, 2005. An introduction to Human Molecular Genetics. 2nd ed. Hoboken, New Jersey: John Wiley and Sons, Inc.
- ↑ Edwards Syndrome, 2012. NHS. Online. Available from: http://www.nhs.uk/conditions/edwards-syndrome/Pages/Introduction.aspx [Accessed 21st October 2013]