Genetic & chromosomal disorders

Screening and diagnostic tests

A number of tests are available that can help identify some of these conditions. Down syndrome, cystic fibrosis, fragile X, neural tube disorders such as spina bifida, and other inherited and chromosomal disorders can all be diagnosed with some level of certainty. However, no test is 100% correct every time.

As the baby develops, different tests can be used to pinpoint particular disorders. These tests can only be done at certain times during the pregnancy when the baby is at a particular stage of development.

There are two types of antenatal testing:

  • screening
  • diagnostic

No test can guarantee a baby will be born healthy, so if you are considering having these tests, it is advisable to seek counselling as early as possible and to ask your doctor about the results and what they mean. You may be faced with having to make some difficult choices when considering the best course of action for you and your family. It can be an advantage having time to plan and prepare.

What we test for

1.    Physical abnormalities such as neural tube defects of the skull (anencephaly) and spine (spina bifida).
2.    Chromosomal abnormalities, of which Down syndrome is the most common. This condition results from an extra copy of chromosome 21.
3.    Genetic disorders. Many inherited conditions can be tested for, including cystic fibrosis, fragile X, spinal muscular atrophy, haemophilia and thalassaemia. These tests are usually only performed on an amniotic fluid or placental sample if clinically indicated e.g. family history or parental gene carrier status.

Chromosomal And Genetc Disorders Graphh