It is over 70 years since the structure of DNA was first discovered and over 20 years since the first human genome was sequenced in its entirety. These phenomenal achievements have enabled the world to evolve technology so we can now interrogate our genomes daily.

Rare and Inherited Diseases

Rare disease is defined as a syndrome present in the general population at a frequency of less than 1/2,000. There are more than 6,000 rare diseases estimated to affect the region of 5% of the world’s population, therefore rare disease is not rare!

For individuals with undiagnosed syndromes, testing their genome increases the likelihood of finding DNA sequence changes which are understood to be the cause of their ill health. Not only does this bring their diagnostic odyssey and ongoing multiple hospital visits and tests to an end but has a wider impact on their families. Families and relatives live through many years of not knowing the reason for the ill health experienced by their loved ones, and often it also affects their own lives. Frequently many couples feel they cannot expand their family due to the uncertainty of whether another child could be similarly affected or are impacted personnally that they have ‘passed on’ the cause of the illness.

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A defined genomic diagnosis for the affected individual provides clarity for the wider family on reproductive options and brings the opportunity to identify family members who may be at risk of being affected by the disease-causing genomic sequence changes thereby opening the door to subsequent monitoring and predictive testing. In essence, giving the opportunity for informed choices regarding life decisions.

Cancer

Genomic testing benefits more than those individuals with a rare or inherited disorder. The development of highly sensitive and specific testing methodologies allows genomic medicine to bring benefits to cancer patients.

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Genomic testing of cancers can identify changes to the DNA sequence in the tumour cells which are not present in the normal cells, indicating that these genetic changes are driving the development of the tumour. This result means that specific medicines can be given which target the functional pathways within the body affected by the genetic changes, thereby truly providing the cancer patient with a personalised treatment. These medicines are usually given daily in a tablet form, so patients do not need to undergo the difficult experience of frequent visits to hospitals or clinics for intravenous chemotherapy regimens. This is another example of how genomic testing can change the way we have known medical care to be given.

Is it Cost-Effective?

This is a difficult question to answer. Historically, genomic testing has been expensive but with the development of new testing strategies and techniques then the costs are reducing. However, with the increase in the volume of genomic testing, the ‘genomics’ budget is rising alarmingly. The true benefits are realised in a different way. For example:

• The decrease in the number of healthcare episodes once a diagnosis has been found
• The reduction in the cost of medical care for individuals who are at high-risk of disease through monitoring or screening prior to disease onset so we can avoid unnecessary treatments and hospitalisation once the disease has developed;
• The delivery of personalised cancer drugs avoiding outpatient treatment visits to clinics and prevention of costly adverse reactions to drugs given in a ‘one size fits all’ manner.

All of these outcomes do reduce healthcare costs but are often not recognised to be a direct result of genomic testing.

The Future

Further advances in the techniques to interrogate the human genome, and our increasing understanding of the impact of genetic changes on our health mean the use of genomic testing will continue to expand across the healthcare systems worldwide.

Already we know of certain genomic variants that determine how medicines are received by our bodies and impact on either their effectiveness or the prediction that they could cause harm and adverse reactions. Such approaches, known as pharmacogenomics are the next step towards individuals knowing the impact of their genome on their healthcare – a true personalised approach to healthcare. This can be expanded into the arena whereby whole genome sequencing of newborns is performed. This is currently happening in many countries to identify diseases where preventative treatments can be given before the babies suffer from symptoms and lead to the prevention of harmful deterioration of their health. Can this be expanded in the future, so all children grow up with a full understanding of their lifetime health profile based on the sequencing of their genome from birth? Only time will tell.