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15th March 2016

Birth defects: do you want to know?

Genetic testing during pregnancy can reveal a rare disease before a baby is born, helping parents to prepare. But just how much information do parents want about their child?

All children are unique but Olivia Farnsworth is a true one-off. The seven-year-old girl rarely sleeps, barely eats and does not feel pain – even when she was hit by a car.

Olivia’s mother Niki says her daughter has no sense of danger and no fear because she cannot be hurt. “She got run over and dragged down the street by a car and she didn’t complain,” she says.

Olivia’s inability to feel pain might sound like a superpower but it is far from beneficial. Her fearlessness leads her to take risks which result in real injuries. And she once chewed through her own lip without noticing because there was no natural pain signal to tell her to stop.

So what is it about Olivia – who is usually a happy school kid – that makes her particularly different? She has a rare disorder called a chromosome 6p deletion.

There are around 15,000 known chromosome disorders. Just 100 are associated with ‘6p’. The condition can cause the sleeplessness, low appetite and inability to feel pain that Olivia’s parents noticed when she was just a few months old. Olivia is thought to be the only person in the world with all three symptoms.

“There may not be anybody out there the same as Olivia,” says Dr Beverly Searle, head of Unique, a charity that works with families affected by chromosome disorders. She says these conditions cannot be cured but the symptoms can be alleviated and families benefit greatly from information and tapping into support networks.


For many of the families affected by rare conditions like these, getting a diagnosis can be a long and arduous process. Understandably, even specialist doctors cannot know everything about the thousands of genetic disorders that exist – and many of the symptoms overlap.

Take Katy, for example. She too has a chromosome 6 deletion. But it was not diagnosed until she was three years old. Doctors initially thought she may have had cerebral palsy but later identified the true cause of her problems.

Parents of children affected by rare conditions also find it difficult to get information about what lies ahead because there are so few documented cases of such disorders.

Katy’s father, Todd, explains how it feels to have so few examples to draw on:

“Today, we are still in the process of discovering where Katy’s condition will lead us in the upcoming years. It’s both a blessing and a curse to have no historical basis to go on. On one hand, we have no pre-set ideas of what she can’t accomplish; but we also don’t know what will work best.”

Changing times

This sense of feeling alone – and the era of delayed diagnosis – is ending as diagnostic technologies get better.

Not only can genetic diseases in children be tested in a simple and increasingly inexpensive manner, but babies can even be diagnosed in utero.

Even before the end of the first trimester of pregnancy, DNA from the baby can be detected in the mother’s blood. And once you have DNA, you have a whole world of genetic information.

This has opened the door to checking the genetic health of unborn children without taking the risks associated with amniocentesis and chorionic villus sampling.

As more people are diagnosed with rare conditions, researchers have an opportunity to learn about a given disease and its prognosis. It is also a chance to connect the growing number of families affected by rare conditions so that they can provide advice and support for one another.

Back to the big question: do you want to know?

The first reason to conduct testing during pregnancy is for peace of mind. In the majority of cases there is nothing to worry about and maternal stress levels should fall once doctors give the ‘all clear’.

If there is something wrong, the question boils down to whether you want to find this out during pregnancy, soon after birth or later in the child’s life.

Certainly, no parent should have to deal with the anxiety of having a sick child with an unknown condition. Is having the joy of a newborn tempered by the shock of finding out about genetic illness much better?

Finding out during pregnancy helps parents to come to terms with the diagnosis, gives time to prepare and to learn more about the condition, and allows people to seek support from charities like Unique.

But there may always be some who prefer not to know; who would rather hope that all is well and wait to see symptoms before seeking a definitive genetic test. It’s a matter of preference.

What would you prefer?