Edward's syndrome, or Trisomy 18, is a serious medical condition that is caused by an abnormal amount of chromosomes within a child's genetic make-up.
Normally, the human body contains 46 chromosomes, which are grouped into 23 pairs. A child with Edward's syndrome has three copies of chromosome 18, hence the name Trisomy 18.
However, it is a rare condition and only one in 3000 pregnancies is affected, although many of these pregnancies will result in miscarriage. While the exact cause is not known, the risk appears to increase slightly along with the mother's age.
The impact of this syndrome is dramatic. A baby with Edward's syndrome will not grow sufficiently within the womb, and the development of the heart and kidneys is severely affected.
Sadly, most babies born with this condition will only manage to survive for a few days. Those babies who do survive will suffer from debilitating medical conditions, such as problems with breathing and eating. Additionally, a child with Edward's syndrome will also suffer from extreme learning difficulties.
Screening tests can be undertaken to ascertain the presence of Edward's syndrome, and these are undertaken by either amniocentesis, where a small amount of amniotic fluid is analysed; or by chorionic villus sampling, where a small piece of tissue from the placenta is examined.