What is genetic testing?
Genetic testing can offer an explanation for why people have certain illnesses. Scientists can look at your genes to diagnose familial hypercholesterol (FH) and other genetic conditions which cause high cholesterol.
The results can make it easier to find the right treatment and to find others in your family who might have the same condition.
What does genetic testing involve?
To have a genetic test, you will need to give a sample of blood or tissue. The sample will be sent to a laboratory so that your genes can be looked at in detail, to see if you have a faulty, or altered, gene which can cause high cholesterol.
Genetics testing can be organised by your specialist doctor at a lipid clinic. It’s not yet available everywhere in the UK, so your specialist will let you know if they think you should have it and if it’s available in your area.
Getting your results
If you are the first person in your family to have a genetics test, it can take time to get your results – around two or three months, or sometimes longer. It’s a complicated test and the scientist need to search for all the genes that could be causing a problem, so it can take time to find the gene or parts of the gene involved.
Sometimes a faulty gene can’t be found. With FH, genetic testing can find a faulty gene in about three out of every four people.
If your test finds a faulty gene
If your test finds the gene which is causing your high cholesterol, your specialist will tell you more about what condition you have, how it affects your cholesterol level, the best treatments for you and how they can keep an eye on your health
Your specialist might also ask for your help in finding other close members of your family with the same condition – this is called cascade testing.
Finding a variant of unknown significance (VUS)
Sometimes a gene will be found that looks different to how it’s expected to, but it’s not clear whether it’s harmless or could cause disease. This is called a variant of unknown significance, or VUS.
Your specialist will talk to you about what this means for you, and they might want to test other members of your family to find out more.
If your test doesn’t find a faulty gene
If no faults or alterations can be found, it could mean that:
- you don’t have a genetic condition
- you have a fault in a gene which is known to cause disease, but it couldn’t be found – some genetic alterations are very difficult to find
- you have a fault in a gene that causes disease, but it hasn’t been identified yet.
Your specialist will talk to you about what it means if no genetic cause for your high cholesterol can be found, and how you can bring it under control.
What happens to your sample?
Your specialist should tell you what will happen to your sample. It’s routinely stored in case it’s needed in the future. Improvements in technology may mean that further tests can be done in the future.
Before you have a genetic test, you should have genetics counselling at a lipid clinic. You might see a genetics counsellor or a doctor or nurse, they can help you to understand:
- what happens when you have a genetic test
- what the results might mean for you and your family
- how having FH or another condition may affect you
- how having FH or another condition might affect any children you have, now or in the future.
You can speak to your genetic counsellor about any practical concerns you have too. For example, whether the results could affect life or travel insurance, job applications and mortgage applications, and what you can do about this.
Should I have a genetic test?
You don’t have to have a genetic test if you don’t want one, it’s a very personal choice.
Before you decide if it’s right for you, talk to your health professional or genetics counsellor about what’s involved and any worries you might have. They can help you weigh up the pros and cons, and what the results could mean for you and your family.
Waiting for and getting results can be a stressful time, and you might feel anxious or even guilty, but on the other hand you might feel relieved. And there are many good points about getting a test:
- it can give or confirm a diagnosis
- you can start treatment quickly
- your health can be monitored
- your future risk of illness could be lowered
- if a gene is found, your family can get tested too.
What about my family – should they be tested?
If you have a genetic condition, testing family members helps to find other people with the same condition before it causes a problem.
If you or another family member has genetic testing and a faulty gene has been found, your doctor will suggest that you or other family members have a test too – as it’s likely that some of them will have the same condition as well.
Most people with FH for example have two close relatives with FH – a brother, sister, parent or child.
It’s much easier to find the faulty gene in other family members once it's been found in one person. The geneticists already know what they’re looking for and don’t need to search all the genes that can cause disease. This is called cascade testing.
Why is it good for family members to be tested?
Sometimes people have FH or another condition but don’t have any health problems like heart disease, perhaps because they have a very healthy lifestyle. It’s even possible to have a condition and not have high cholesterol. They could still pass the gene onto their children who could go on to have high cholesterol and health problems. So finding out if they have a condition means their whole family can get treatment if they need it.
Telling your family you have a condition
If you have FH or another condition, it’s likely that your doctor will want your help to contact your family. They might give you a letter to pass on which explains about the condition, the health problems it can cause, and how the genetic test works. Passing on this letter can help prevent heart disease and stroke in your family and their children for generations to come.
Some people find it hard to explain to their family what FH is and why it’s important to get a test. Some people are not in touch with some members of their family or aren’t on good terms, which can make contacting them or talking to them difficult.
If you would like any support in contacting or talking to your family, our specialist nurses or your genetics counsellor may be able to help.
How will getting a genetic test affect my insurance?
If you have a diagnosis of a long term inherited condition, such as FH, your life insurance could cost more.
But if your condition is being properly managed, the diagnosis does not necessarily mean you are ‘high risk’ for an insurer or mortgage lender. You could ask your health professional for a supporting letter to support your application.
At the moment, there is a temporary agreement in place which stops insurance companies from asking about the results of genetic testing. But you do have to disclose a family history of serious inherited disorders and many insurance companies will ”load” your insurance fee as a result.
Find out more about insurance for people with serious health conditions by contacting the Association of British Insurers.
Genetic Alliance have some very helpful frequently asked questions and answers about genetic conditions and insurance.