Trying For A Baby / 29 November, 2017 / Dr Ellie Cannon

Home Genetic Testing Kits – Should We Be Getting Tested Pre Pregnancy?

We talk to Dr Ellie Cannon about a new home genetics testing kit, and whether testing for health problems that you could be carrying should become part of a pre-pregnancy routine. 

We talk a lot about health and nutrition to prepare for pregnancy but have you thought about your
genes? Genetic testing prior to conceiving is not a routine part of getting pregnant for most women
in the UK, although it can be in other countries. But as well as getting yourself fit and healthy to get
pregnant, genetic testing may also be something you want to consider.

Some health problems that babies and children develop can be carried on your and your partner’s
genes. Cystic fibrosis (CF) is one of those. 1 in every 2,500 babies born in the UK each year are
diagnosed with cystic fibrosis, a lung condition which causes clogged, sticky lungs leading to long
term damage and reduced life expectancy. It is an inherited condition which is passed on by faulty
genes: a baby needs two parents to be ‘carriers’ of the faulty CF gene to develop the condition.
Unfortunately there are 2 million people in the UK carrying the CF gene and often they don’t know
about it. If two carriers have a baby they have a 1 in 4 chance of the baby having cystic fibrosis. If
only one of you is a carrier, the baby cannot develop CF but may also be a carrier.

In 2007, cystic fibrosis testing for all new-borns was introduced in the UK. The tests are carried out at
the new-born heelprick test in the first week or two after birth. If a baby is diagnosed with cystic
fibrosis, there are a number of treatments available to help reduce the symptoms of the condition.
If you want to know if you carry the gene firstly it is worthwhile checking with everyone in the family
if there are any relatives with cystic fibrosis. Your partner should check too. If you do, you can speak
to your doctor about a genetic referral before you start trying to conceive to be tested for the faulty
gene.

If you are unsure if you or anyone in your family is a carrier, then a personal genetics testing kit may
be a good solution for would-be parents to find out if their baby is at risk of developing cystic
fibrosis.

At home personal genetics testing products such as 23andMe relies on saliva samples which you
take at home to collect your DNA and look specifically at some of your genes. 23andMe has reports
on your carrier status for certain diseases, like cystic fibrosis or sickle cell anemia. These reports do
not tell you your own personal risk for the condition, rather the likelihood you may pass down a
harmful genetic mutation to your children, who may be affected by the disease if your partner is also
a carrier.*

At home genetics testing is not for everyone. As a GP, I am used to being able to give people a
straight answer about what they should and shouldn’t do when it comes to better understanding
their health and taking care of themselves but it really is a very personal decision whether or not to
go through the process. Some couples will very much want to know about these very risks from their
genes and others won’t. It is an important conversation to have.

If you are planning to get pregnant have a chat with your family and your partner’s and see what
family history you may need to know about. Sometimes families are very coy or private about these
details but it can be really important for the future generations to know about. Knowledge is always
empowerment and means you can make the right choices for you and your future family. If you
have any concerns about your own or your partner’s health in relation to conceiving, always have a
chat with your own doctor.

*The Cystic Fibrosis carrier status report is indicated for the detection of 28 variants in the CFTR gene
and is most relevant for people of Ashkenazi Jewish, European, and Hispanic/Latino descent.
23andMe carrier status reports for cystic fibrosis and sickle cell anaemia are intended for adults and
provide information about carrier status and genetic risk for these conditions. The test isn’t intended
to diagnose any condition or tell you about your risk or your child’s risk for developing a condition.
For more information on cystic fibrosis visit www.cysticfibrosis.org.uk.

Dr Ellie Cannon is remunerated in her capacity as a UK spokesperson for 23andMe.