In this explainer episode, we’ve asked John Pullinger, Senior Bio Sample Operations Manager at Genomics England, to explain what it means to go on a diagnostic odyssey. You can also find a series of short videos explaining some of the common terms you might encounter about genomics on our YouTube channel. If you’ve got any questions, or have any other topics you’d like us to explain, feel free to contact us on info@genomicsengland.co.uk. The episodes mentioned in the conversation are linked below. Hope for those with no primary findings The impact of a genetic diagnosis on mental health You can download the transcript or read it below. Florence: What does it mean to go on a diagnostic odyssey? I'm joined by John Pullinger, Senior Bio Sample Operations Manager for Genomics England to find out more. So, John, first of all, can you explain what we mean by diagnostic odyssey?   John: Yes, of course. The diagnostic odyssey is a term used to describe the journey that many people with rare conditions and their families undertake to receive an accurate diagnosis, a journey that takes on average over five and a half years.  The rarity of the condition means that there are few, if any, other people affected by it, for doctors to draw their experience from. Some individuals might never receive a diagnosis.  My job involves making sure that samples sent through the Genomics England processes can travel smoothly from the NHS hospitals to be sequenced and the results be reported back to the individual. We try and minimise the amount of time that samples and associated data is in our care.   Florence: And for people listening who might not know, could you explain why it sometimes takes a long time for people to receive a diagnosis?  John: 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 how to test for them. In addition to this, some conditions affect multiple parts of the body. For example, skin, the heart, and the lungs. In these cases, there will be a need to visit specialists from multiple departments, and each will be looking specifically at their own area.  This could lead to referral loops where the patient needs to consult multiple healthcare professionals, all of which contributes to the time taken to receive a diagnosis. Since, for the majority of rare conditions, there is an underlying genetic cause. This means that most individuals who get a diagnosis will receive one through genomic testing, whether that be whole genome sequencing as offered here at Genomics England, or more targeted panel testing.  Typically testing will identify a particular gene, which is known to be linked to a specific condition. For certain conditions, it requires a real expert in the condition to even think about testing for it. Sometimes a condition will present in a way that is different to most other people who have it. So they may have symptoms that others don't. This also adds to the buildup of time taken to receive the diagnosis.  Florence: So, you mentioned earlier, John, that the diagnostic odyssey lasts an average of five and a half years. Can you explain what kind of effect this long waiting time has on individuals and their families?  John: Absolutely. One aspect of the diagnostic odyssey that is important to recognise is the physical effect of the as yet undiagnosed condition that's present and affecting the individual and their family on a daily basis. Those with rare conditions may be affected by a range of emotions connected to the ongoing journey that they're on, including feelings of isolation.  Also stress and anxiety. The fear of unknown can have a massive knock-on effect on the mental health of the individual and their family. And it's important to recognise the signs of this so that people can take steps to manage their mental health. Many rare conditions first present themselves in children and young