What is inflammatory bowel disease?
Inflammatory bowel disease is a chronic condition that typically affects the gut but can also affect other parts of the body. And the most common types are Crohn's disease, ulcerative colitis, and inflammatory bowel disease, unclassified. And for most patients, these are going to be caused by a mixture of genes and also the environment, so we're thinking about bacteria in the gut, but for a very small number of patients, we know that it's a purely genetic cause and it's really important to identify these individuals in these families because it might change what treatment they have.
Why might we be offered genomic testing?
So this test is quite new on the NHS and it's very specifically used for patients with a high index of suspicion for inflammatory bowel disease caused by a single genetic problem. And the main reason that we might choose a family or a patient for testing would be the age at which that patient was diagnosed with inflammatory bowel disease.
That means that for all patients aged less than two when they first had that diagnosis, they should be sent for this testing. And for patients aged between two and six, if there are specific additional features such as problems with the immune system or features of auto inflammatory problems, maybe other issues such as joint problems or skin problems, then we would also consider them to be sent for testing.
For other cases, including older children and potentially even adults, there will be specific situations where we want to do that testing, but that will be managed on a case by case basis.
What is genomic testing in inflammatory bowel disease?
So genomic testing or genetic testing for single gene cause of inflammatory bowel disease is looking for a number of conditions across about 100 different genes that might lead to the inflammation within the gut. Now we know that that's only going to be for a very small number of patients, even for those who are eligible for the testing, those who are aged less than two or those aged between two and six with specific other features. But it's really important that we identify what genetic changes, changes in the DNA there may be because it might have specific implications for the treatment or management of that patient and potentially for the entire family.
What does it involve?
Your doctor or nurse will talk you through the testing and go through some forms to confirm that you understand the process and what the results mean. The test itself is a simple blood test that can be done at the same time as other bloods are being taken. Normally we try to send blood samples on the patient and their mum and dad, which is called a trio, this is to look for changes that can only occur in the patient with inflammatory bowel disease but may have been inherited partly from mum or dad.
When will we get the results back?
The genetic testing is very complicated and it can take up to 6 to 9 months and sometimes longer to get these results back into the clinic. This is mainly because we want to interpret these in a correct way and make sure that any findings we report back to the family are completely right, as these can have significant impacts on treatment and management for both the patient and for their entire family.
What is likely to happen with the results?
In most patients, we won't find a genetic cause for their inflammatory bowel disease. However, it's still important to know this as it can be really useful for a family, and it can also be useful to know what conditions it is not. For those patients where we do find a genetic cause for their inflammatory bowel disease, it can have specific impacts on their treatment and their management and can also have an impact on their family as it may be important to test other siblings for this condition. It also is important that we know about genetic codes because even if there isn't a treatment right now, in the future there may be treatments that we can use much earlier. And it is also important that we know about this so we can discuss it with national experts around the country to give patients the best options for treatment and management as possible.