Known as the DNA doctor, Melita Irving is passionate about … well, DNA! She works as a consultant in clinical genetics at Guys and St Thomas’s Hospital, specialising in conditions that affect the skeleton. Last year Melita’s book ‘The Human DNA Manual’ was published by Haynes, covering everything from how DNA catches killers to identifying long-dead kings! Who’s the book for? Anyone with DNA!

At RAREfest20 Melita will be doing a live DNA extraction, not on a human (phew!) but on a strawberry. She’ll be interviewed by Dr Lucy Mackay from Medics4RareDiseases, a charity that drives an attitude change towards rare diseases amongst medical students and doctors
in training.

We caught up with Melita ahead of  RAREfest20 to talk all things DNA…

What does a genetic scientist actually do?
Genetics impacts upon every system in the body and affects everybody! The most common type of referral into the clinical genetics service is a child who is not meeting their developmental milestones. Maybe they’re not growing as expected. Maybe they look different. Maybe they have an abnormality, like a hole in the heart. The question needs to be asked: Is this child just unlucky or could there be one single explanation that accounts for everything – and could it be genetic? Being a genetic scientist is exactly like being a detective, looking for that key clue that leads you down the right path and not being confused by any red herrings that are thrown in the way.

How has technology changed the way rare diseases are diagnosed?
There are 20,000 genes, all of which can go wrong, and there are 8000 listed genetic disorders that are classed as rare diseases. Up until very recently we’ve been absolutely hamstrung by our ability to do genetic testing for diagnostic purposes. We used to put all the clues together, do our ‘best guess’ diagnosis, see if there’s a test available and then get that test done. After all that, you find you’ve been on the wrong path the whole time. So, you’d have to come back up that path and go down another one. Rinse and repeat. It could be a very long drawn out process that never led to any answers.

However, we are now in an era where we can do high throughput genetic testing. We are able to look at all the genes in one go and focus all our attention on those we think are relevant to the story. You can go down ten different paths at the same time! We are anticipating that in the next year or so the speed at which we get to diagnosis through genetic testing will be much quicker. That’s all down to technology and whole genome sequencing.

Why are rare diseases so hard to diagnose?
Not many people know about rare diseases and there are so many of them, plus there’s no one type. You might have the same diagnosis as someone else, but the format of your rare disease is completely different.

Another problem is at medical school we are frequently told not to worry about rare diseases and concentrate on more common conditions. This means rare diseases are never fully appreciated and that bit of the ‘doctor brain’ never gets to develop. Medics4RareDiseases are pushing for more learning at medical school and in early stage careers, so rare diseases become something you must think about.