Down syndrome is a genetic disorder otherwise known as trisomy and it is where an individual has inherited an additional or extra copy of a particular chromosome. In the case of Down’s syndrome, the affected individuals have three copies rather than two of chromosome 21. The consequence of this additional copy is that it changes the balance of the body resulting in characteristic intellectual and physical features.

Down Syndrome

There are three kinds of Down’s syndrome: regular trisomy 21 which is where all the cells in the body have an extra chromosome 21 and is the most common type of the condition with nearly 94% affected with Down’s having it; translocation, which is where extra chromosome 21 material attaches to another chromosome, and four percent have this type; and mosaic, which is where only some of the cells have additional chromosome 21. This usually has milder features than the other two types and only two percent of affected individuals have mosaic.

Down syndrome sufferers look different to normal people and usually have a flat type of facial profile with eyes slanting upwards. Smaller ears, protruding tongue and a flat back of the head are other features. Individuals affected tend to be shorter than normal, have poor muscle tone and have broad, short hands. Half the affected individuals have a heart defect, which can be treated in some, but not others. Some have problems with their gut, making it difficult to eat while increasing the risk of constipation and thyroid problems.

There is no cure for Down syndrome but there are treatments available for the accompanying symptoms as well as support for the learning difficulties.