Finding the missing pieces – how genomics is helping to diagnose and treat rare diseases
Last Reviewed 27/02/2020
By Professor Dame Sue Hill and Russell Viner
For every 17 people reading this article, statistically one of us will be affected by a rare disease at some point in our lives.
Put another way some seven per cent of the population in the UK, or roughly 3.5 million people, are living with one of the 6,000 rare diseases we currently know about – so the need, and the challenge, is quite clear. Rare diseases are a major part of the work of paediatricians, across general, community and specialist paediatricians, and all parts of the child health workforce.
This is why Rare Disease Day and groups like the Genetic Alliance UK and the British Paediatric Surveillance Unit play such important roles in gathering data and information about rare diseases and raising awareness about the impact they have on peoples’ lives.
Devil is in the detail
80 per cent of rare diseases have a genetic component and we can currently only test for about half of these conditions.
This means the key to diagnosing these remaining unknown conditions lies in delving into our DNA – this is exactly what the NHS Genomic Medicine Service (GMS) is doing.
The GMS is harnessing the power of genomics, the study of genes in our DNA and their function, to help us predict and prevent certain diseases, develop more precise diagnoses and more personalised and targeted treatments – a world-first for a national healthcare system.
This means it could help clinicians identify the genetic causes of rare conditions and even the treatments for them…and it already is.
‘A big weight has been carried off my shoulders’
The sad truth is that babies and children are most likely to be affected by a rare disease with as many as 30 per cent dying before their fifth birthday.
In many cases it takes years to make a diagnosis and, if it is even possible, develop a treatment or provide better management of the condition. This diagnostic odyssey takes it toll on the patient and their loved ones with what can involve numerous visits to hospitals and specialists, and in this time, conditions can worsen and sadly patients can pass away before a diagnosis is even found.
We need to ensure the power of genomics is harnessed earlier in the patient’s journey to cut this odyssey short. Earlier diagnosis means an earlier intervention and potentially saving a life.
This is why the GMS has recently launched a Rapid Exome Sequencing service for critically ill infants. This approach analyses over 20,000 genes and offers a much faster route to finding any abnormalities in the DNA leading to faster diagnoses and much earlier decisions about care.
Since it started in October last year the service has had more than 140 referrals with almost 40 per cent of patients receiving a diagnosis they couldn’t get before.
The power of this kind of sequencing can be demonstrated by the case of Arvin Fejzullahu, who struggled with his speech and started suffering from epilepsy. His mum, Beksida, first flagged her concerns when he was one, but it wasn’t until he was offered rapid exome sequencing that the gene causing these problems was identified. This meant that Arvin could get the support he needed to fulfil his potential.
This discovery also helped determine that their second baby did not carry the same gene as Arvin and in the words of Beksida, “a big weight has been carried off my shoulders.”
Empowering all NHS staff
It’s cases like Arvin’s that have demonstrated how powerful genomics can be for paediatricians on the front-line who currently must support worried parents and families with few answers.
And it’s not just paediatricians who will benefit from genomics being embedded into everyday care in the NHS – understanding the genetic basis for so many conditions from heart disease to diabetes can help not only lead to an early diagnosis but also help prevent the onset in the first place.
The first step towards this vision becoming a reality will take place later this year when we introduce Whole Genome Sequencing for patients with suspected rare diseases and for all children with cancer and adults with certain cancers.
Of course, to remain at the cutting-edge, there’s a need to set in place the right learning resources and tools to help staff in their professional practice on areas such as the latest scientific developments right through to ethics, counselling and signposting.
In the near future, all paediatricians will need to have a working understanding of the types of information we get from genomics and how we share those with families.
Getting patients the support they need
We don’t want genomics to be a rare thing in the NHS either – the GMS aims to embed genomics in all aspects of care patients receive so they can live life to its fullest.
For so many with a suspected rare disease, waiting to understand what is wrong, even if its treatable, can feel like an endless nightmare. Genomics offers hope that this diagnostic odyssey could be cut short and the missing piece of the puzzle found. But diagnosis can’t just be in isolation – the NHS as a whole is also evolving and responding to the opportunity of genomics in the delivery of patient care.
It’s a game-changer.