Genetic disorders: Down’s, Edwards’ and Patau’s syndrome

Posted: 08/11/2022

This is the seventh article in our birth injuries series, following the previous post on facial paralysis in newborns. In this article we will discuss genetic disorders, focusing on three main conditions routinely screened for in pregnancy: Down’s syndrome, Edwards’ syndrome and Patau’s syndrome.

What are genetic disorders?

Genetic disorders are conditions caused by changes (called mutations) to either the genes or the chromosomes. Genes act like an instruction manual, and are passed on from parent to child, carrying information determining an individual’s traits. Genes are contained within the chromosomes, which are inside almost every cell in the body. Genetic disorders can be either inherited or non-inherited. Inherited genetic disorders are caused by mutations to the genes. Most chromosomal disorders are not inherited; they are caused by missing or extra chromosomes.

Can genetic disorders be tested for in pregnancy?

In pregnancy, two main types of tests can be used to see whether a baby has a genetic disorder:

• screening tests – which tell you the likelihood that a baby has a certain disorder; and
• diagnostic tests – which confirm whether a baby actually has a certain disorder.

Three of the main genetic disorders routinely screened for are: Down’s syndrome, Edwards’ syndrome and Patau’s syndrome.

What do these screening tests involve?

Combined test
Between 10 and 14 weeks of pregnancy, a ‘combined test’ is offered, which involves an ultrasound scan (usually at 12 weeks) and a blood test. During the scan, the fluid at the back of a baby’s neck is measured – this is the ‘nuchal translucency’. Results from the blood test, maternal age, and nuchal translucency are all used to calculate the risk of the baby having Down’s, Edwards’ or Patau’s syndrome. The risk will be given as either a ‘high-chance’ or ‘lower-chance’ result.

Quadruple (‘quad’) test
If a pregnancy has progressed by more than 14 weeks, another blood screening test, known as a quad test, is offered. This can be given between 14 and 20 weeks of pregnancy, only tests for Down’s syndrome, and is not as accurate as the combined test.

If the combined or quad tests produce a ‘higher-chance’ result, options include:

• non-invasive prenatal testing (NIPT) – a blood test giving a more accurate screening result; or
• diagnostic testing – testing of the amniotic fluid (amniocentesis), placental tissue (CVS), or fetal blood, which will confirm whether or not the baby has Down’s, Edwards’ or Patau’s syndrome.

If diagnostic testing confirms one of these conditions, the option of termination of the pregnancy will be offered. Although children with Down’s syndrome can live long and fulfilling lives following developments in healthcare, very sadly babies with Edwards’ and Patau’s syndrome are born with severe physical abnormalities, and the majority will die during their first year.

20-week scan
Sometimes called the ‘anomaly’ scan, this is offered to everyone between 18 and 21 weeks of pregnancy. It is used to check the physical development of the baby, and any characteristics of physical conditions, including Edwards’ and Patau’s syndrome.

How can screening go wrong?

Where mistakes are made with antenatal screening leading to a ‘wrongful birth’, it may be possible to bring a claim. Such mistakes may involve:

• failure to carry out or accurately report on antenatal screening;
• failure to advise parents on the results of screening; and
• failure to undertake further testing if a higher risk result is identified.

If you have been affected by any of these issues and want some professional advice, our specialist birth injury team is here to offer an informal discussion to let you know what your options are. Please call 0800 328 9545, email clinnegspecialist@penningtonslaw.com or complete our online assessment form.

Previous articles in this series:

• Bleeding after giving birth - what does it mean and when can it cause problems?
• Cerebral palsy: causes, common features and making a claim
• Shoulder dystocia: what is it, how is it caused, and what are the long-term effects?
• Erb's palsy: what is is and how to bring a claim
• Facial paralysis: why it occurs in newborn children, and how it should be treated

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