The Student
Mystery illnesses diagnosed through genome study
by Louise Munro, 22/01/16

In 2003 a significant breakthrough was announced. The Human Genome Project  (HGP) had successfully read the entire genetic code of a human being, comprising 20,000 or so genes and the DNA in between. The HGP was a huge international collaboration, with the UK at the forefront, following in the footsteps of other British scientists who revolutionised the field, such as Watson and Crick for their discovery of the double helix, and Sanger for his sequencing technique.

The first genome took 13 years and £2 billion, but due to technological advances it is now possible to read an individual’s genome in just two days at a fraction of the cost; as such there is opportunity to translate scientific discovery into potentially life-saving realities for countless patients.

In 2012, the UK government launched a pioneering project. The 100,000 Genomes Project hopes to bring new diagnoses and transform the use of genomics in the NHS – specifically with regards to rare diseases and cancer due to their collective impact on public health. In the UK over 300,000 new cancer cases are reported yearly, and with an aging population this number will continue to increase. It is estimated that one in 17 will be affected by rare diseases, with 50 per cent of new cases occurring in children.  Both areas of disease are often characterised by genomic changes and so genomics has the potential to improve speed of diagnosis and patient care. Cancer for example occurs when DNA in a normal cell is mutated, enabling a tumour to grow and spread. Comparing DNA from both the tumour and normal cells allows the precise changes to be identified and targeted by new therapies.


Genomics has a huge range of potential applications relating to personalised medicine. An example is whether a breast cancer is positive for the HER2 gene. If this is the case, then the specific drug treatment Herceptin will be very effective. Genomics can also be used to assess how well a cancer may respond to radiotherapy – which could translate to fewer exposures for patients, and determine how many insulin-dependent Type 1 diabetics would be better with tablets. The list goes on.  There is potential for more precise and rapid diagnoses, new devices, treatments and, with time, cures.

A number of patients have already benefitted, some because a better treatment was identified and others because their conditions were diagnosed for the first time. Most recent are the two four-year-old girls whose participation enabled the determination of the underlying genetic changes, providing them with a name for their disorder and the opportunity to plan for the future. Both children were diagnosed at Great Ormond Street Hospital. Georgia Walburn-Green suffers from poor eyesight and stunted growth, whereas Jessica Wright has had seizures since she was an infant. The genes responsible for these problems have been discovered, which is life-changing after years of uncertainty.

There is still a long way to go before rare diseases and cancer are truly understood and, for now, many participants remain undiagnosed due to the unclear roles of some genes in disease, but this will change as more genomes are sequenced.