Genomics 101: What is the diagnostic odyssey?

In this series, ‘Genomics 101’, we go back to basics and explore some of the most important topics in genomics. In this blog, we explain what it means to go on a diagnostic odyssey.

First things first, what does diagnostic odyssey mean?

People affected by rare conditions must often take a long and difficult journey to receive an accurate genetic diagnosis.

We call this journey the ‘diagnostic odyssey’, and its average length is 5.6 years.

Why do we use the term 'odyssey’?

The term ‘odyssey’ refers to a long and complicated journey, usually in quest of particular goal or answer.

For people affected by rare conditions, a journey like this is so common that the community adopted the term ‘diagnostic odyssey’ to describe the process of getting a diagnosis.

Why can it take a long time to get a diagnosis?

There are estimated to be over 7,000 rare conditions. This means that healthcare professionals may not be familiar with all of them, and so may not recognise them or know to test for them.

Additionally, lots of rare conditions affect multiple parts of the body. For example, Marfan Syndrome is a rare condition that affects the heart, eyes, blood vessels and skeleton.

When people have conditions like this, they often need to visit multiple different specialists across several departments.

This involves lots of different appointments, sometimes with differing medical opinions, all of which add to the time it takes to reach an answer.

Genomic tests and the diagnostic odyssey

It is estimated that 80% of rare conditions have a genetic cause. This means that most patients who do receive a diagnosis will get it through genetic or genomic testing.

However, the process of getting a diagnosis through a genomic test can still be lengthy and complicated.

Why can genetic testing take a long time?

Typically, genetic testing will look to identify a particular gene known to be associated with a certain condition or set of conditions.

This means it often requires an expert to even think about performing the test.

Additionally, patients can be affected in different ways by the same condition. Some people may display symptoms that others don’t, even if they both have the same genetic change.

This can lead to the wrong genes being tested for or the wrong type of testing being performed, all of which contribute to the time taken to receive a diagnosis.

Do all genetic tests lead to a diagnosis?

No, not all people who get a genetic test will receive a diagnosis.

This may be for a few reasons, for example if the condition being tested for isn’t genetic, or if it is genetic, but the gene that’s causing it hasn’t been discovered and recorded yet.

Additionally, genetic tests can also result in something known as ‘variants of uncertain significance.’

This means that genetic changes have been found from the test, but that scientists and clinicians aren’t certain whether they are responsible for causing the condition or not.

How can the diagnostic odyssey affect people?

This is a very important question, and the diagnostic odyssey can affect people in lots of different ways, physically, mentally, and emotionally.

Lisa Beaton, member of the Participant Panel at Genomics England, explains her experience of waiting for answers surrounding her daughters rare condition.

To hear more from our conversation with Lisa, listen to the full Behind the Genes Podcast.

How can people access support on their diagnostic odyssey?

There are lots of resources and support groups to help people affected by rare conditions.

For example, Genetic Alliance UK is an alliance of over 200 charities and support groups, which aims to improve the lives of people in the UK living with rare and undiagnosed conditions.

You can visit the Genetic Alliance website to access support and resources surrounding your journey with a rare condition.