What is genetic counselling and how could it help you?

Posted: Thursday 5 May 2022 at 14:16

Genetic counsellor Hannah Knight has spoken about why many people choose to find out what gene is causing their condition. 

In her role at Moorfields Eye Hospital Hannah Knight helps people understand the advantages of genetic testing, as well as its limitations and what any results mean. 

As part of the Macular Society's My Macular and Me webinar series, Hannah joined professor Andrew Webster, to dispel some of the myths surrounding the topic. 

What does a genetic counsellor do?

Hannah said: “A lot of my job involves information giving, both prior to genetic testing and post genetic testing.

“Talking about what testing involves, what are pros and cons and limitations of testing and also giving information of where people might get support.”

She added: “When someone has a genetic result we know that that the risks to any of their relatives can be anywhere from incredibly low up, to 50 per cent. So, one of the big questions people ask when they get their results is what does this mean for my family or my children, or any children I might have in the future?”

“Really that’s a big part of my role helping people to understand what the risks are and if there are any options in terms of testing for relatives or family planning, testing during pregnancy or things like that.”

Who can get a genetic test?

Testing is offered to all patients who are diagnosed with a genetic condition. But, the decision to have a test is entirely personal. Children under the age of 16 are not offered testing, unless there is something which can be done about their condition.

Why should I get a genetic test?

Hannah highlighted the three main reasons she encouraged her patients to get a genetic test:

  • Firstly a genetic test can help understand what’s causing a condition, which can provide further information about prognosis, such as whether this is a stable condition or something that’s likely to progress.
  • A test can also give us info about how the condition has been inherited, whether it’s something that has been passed on by one parent, or both.
  • Finally, testing can also give information on things unrelated to the eyes patients may want to be made aware of.

But, while Hannah encourages people to get a genetic test, she also highlighted its limitations, including that it doesn’t often change the management of the condition or open up any options for treatment.

If it’s not going to change anything for me, what’s the point?

“A lot of people like to know what’s causing their condition,” Hannah said. “Even if it’s not about changing anything for them, it’s about giving them information, empowering them and it means they can make decisions that are right for them and share information with their family as well.”

Is there a guarantee I will get an answer?

With any genetic test, there is no guarantee an answer will be found.

But Hannah highlighted the likelihood of finding a faulty gene has been improved by the process used within the NHS, using whole genome sequencing. This involves looking at all of the genetic information in the body, not just the eyes.

“The benefit of this is we’re discovering new genes all the time,” she said. “New genes that can cause these conditions, new variations in these genes, so if in the future we discover a new cause of these conditions, it means we can go back and re-analyse data.

“Even if at the moment you’ve gone through genetic testing and we haven’t found the cause of your condition, it’s not necessarily going to stay that way – we’re getting patients a year after testing, where we’re going back and we’re finding the cause for their condition.”  

How is the test carried out?

Hannah highlighted that one of the biggest reasons people don’t want a test is due to a fear of needles. She said: “Genetic tests generally need a blood sample.”

But she said, where possible, they can try and offer saliva samples.

Watch the full webinar Inherited macular disease - should I know my gene? 

If you'd like more information on genetic testing, visit our website or get in touch on 0300 3030 111 or help@macularsociety.org