All human cells are made up of 23 pairs of Chromosones. They are numbered 1 – 22 with the final pair being the X and Y chromosones which determine a child’s sex.
These pairs of chromosones are formed when the sperm first reaches the egg, and as the cells divide and the embryo develops, these chromosones are copied into other cells.
Occasionally mistakes arise, and these cells do not copy as exact pairs, and an additional chromosome is produced. In the case of Edwards Syndrome, instead of having one pair of chromosome number 18, you have the pair plus an additional one (i.e. 3) , which is why it is also sometimes called Trisomy 18.
As the embryo develops, in some instances this mistake will be copied into every single cell that it produced, which means that the baby will have what is called Full Edwards Syndrome. In other instances, it will only copy across to a few cells, meaning that some cells have the correct number of pairs, and some don’t. This is referred to as Mosaic Edwards Syndrome.
Edwards Syndrome is a very serious genetic disorder. In most cases it is life restricting. Many fetuses will die in the womb and not survive until childbirth. Should Edwards Syndrome be identified during pregnancy, many women will be advised to terminate the pregnancy.
Of the few babies that survive to childbirth it is estimated that around half do not survive the first week of life. Most do not survive to see their first birthday, and as few as 1% survive to the age of 10 (mainly mosaic). For those that do survive, the disorder can result in severe mental and developmental disabilities.
A baby with Edwards Syndrome may have some or all of the following features:-
• Heart Defects
• Kidney problems
• Intestinal issues
• Rocker bottom feet
• Low set, malformed ears
• Clenched fists
• Delicate facial features
• A small head with a large back portion
• Overlapping fingers
• Cleft Palate
It is estimated that one in every 6,000 live births results in Edwards Syndrome. Most instances are purely down to bad luck, however it is possible to be a carrier of this genetic disorder without having it yourself. There is a greater risk of losing a male fetus with Edwards Syndrome in pregnancy than female, and your risk of having an Edwards Baby increases with maternal age.