Down Syndrome occurs as a result of an error in cell division during pregnancy, when an embryo has three instead of two copies of chromosome 21. This is known as Trisomy 21 and is the most common form of down syndrome, affecting 95% of those diagnosed. Translocation, another form of down syndrome, occurs when part of chromosome 21 branches off and attaches itself to a different chromosome, and affects approximately 2 to 3 percent of those with down syndrome. It can be spontaneous or inherited from a parent. Lastly, there is Mosaicism, where early cell division occurs after conception and also results in three copies of chromosome 21.
Individuals with down syndrome will often appear similar to each other and tend to have a smaller or flat-shaped nose, slanted or almond-shaped eyes, a smaller body frame and limbs, as well as low muscle tone. Children with down syndrome will also have both intellectual and physical delays, including cognitive impairment, but the level in which these abilities are affected cannot usually be predicted. One common misconception is that individuals with down syndrome are completely disabled and cannot function without help. However, it is entirely possible for some individuals with down syndrome to be able to live independently and do everything a human being can do – including walking, reading, writing, and even working and forming personal relationships. To ensure that a child with down syndrome can live as normal a life as possible, going for physical therapy and teaching them how to read and write early on can help to build that foundation and improve their abilities.
Another common misconception of down syndrome is that those who have been diagnosed with it will die young. While the average life expectancy of someone with down syndrome is approximately 60 years of age, some individuals with down syndrome has lived as long as 80 years old.
For more information on down syndrome, including community resources, webinars and other publications, Dr. Ali Ghahary, a family physician from Vancouver, recommends visiting the Canadian Down Syndrome Society website at CDSS.ca.