08.02.17
Is it time to rethink testing for inherited cardiac conditions?
Source: NHE Jan/Feb 17
Dr Mike Knapton, associate medical director at the British Heart Foundation (BHF), discusses the need to support cascade testing for inherited cardiovascular conditions.
Inherited cardiovascular conditions (ICCs) are a group of genetic disorders that primarily affect the heart, including cardiac electrical systems and blood vessels. Sadly the first indication that an ICC is present in a family is the sudden and unexpected death of an apparently healthy child, teenager or young adult. Research is helping us finally understand the extent of inherited cardiovascular conditions, such as hypertrophic cardiomyopathy (HCM) or familial hypercholesterolaemia (FH) among the population. Genetic testing is now possible, which helps patients, their family and clinicians offer better risk assessment, accurate diagnosis and management.
ICCs affect more than half a million people across the UK and as research improves, we get more accurate estimates for prevalence. It was originally thought that FH affected one in 500 of the population but recent research suggests this is more like one in 250, a similar prevalence to Type 1 diabetes mellitus.
Current situation and problems
It is not uncommon to discover that a patient has FH, a condition which causes high levels of LDL cholesterol in a person’s blood, or an inherited heart condition such as disease of the heart muscle, like HCM, when it is too late. Of the expected 240,000 FH cases prevalent in the UK, only 20,000 are recognised.
FH and HCM are inherited conditions where a mutation in a gene is passed on through a family, with a 50% chance of inheriting the condition from an affected parent. Many of the gene mutations have now been identified, allowing genetic cascade testing of first degree relatives to be diagnosed before the clinical signs or sudden death occur. Research into the genetic cause and treatment of FH, much of this funded by the BHF, has demonstrated that early treatment of these patients can return someone’s life expectancy back to that of someone without the condition.
The National Institute for Health and Care Excellence (NICE) published guidance on the identification and management of FH in 2008, but patients are still not being routinely referred to specialist clinics for the genetic test to confirm diagnosis. This has a knock-on effect in that the relatives of the affected individual are not identified with the inherited condition either.
Part of the problem is that there is a lack of awareness of FH and other conditions, both in the general public and amongst healthcare professionals. For example, it’s not uncommon for people in their middle-age to have raised cholesterol levels. A routine blood test revealing an abnormally high cholesterol level (above 7.5mmol/l) should raise the possibility of FH and the need for genetic testing. The NHS Health Check Programme is an opportunity to find the missing cases, offer a genetic diagnostic test and cascade treating of first degree relatives.
Obstacles such as relatives living abroad or in different regions, or losing touch with family members, makes it more difficult for health services. This is why cascade testing is so important.
How should it work?
Once a patient has a genetic diagnosis for an inherited condition such as FH or HCM, and they are put on the correct treatment pathway, testing should then cascade through immediate family members. This targeted approach is the most cost-effective way to find more people affected by these conditions.
The BHF has invested £1.5m in funding 27 FH nurses across 12 UK sites over a two-year period to support cascade testing for FH. Evidence from BHF-funded pilot projects has shown this method is feasible, as well as being clinically and cost effective. The BHF is now investing in a similar model of care to identify people with HCM. These now need to be rolled out across the UK.
Benefits for the future
The NHS has made a commitment to be the first healthcare system to embrace personalised medicine, described as “a move away from a ‘one-size-fits-all’ approach to the treatment and care of patients with a particular condition, to one which uses new approaches to better manage patients’ health and target therapies to achieve the best outcomes in the management of a patient’s disease or predisposition to disease”.
In addition, the 100,000 genome project is developing at pace and the individuals identified with a gene mutation, as a result of the individual genome sequencing, will need models of care to support them and their families. Evidence from BHF-funded research is providing tangible examples of personalised medicine to make the NHS ambition a reality.
The greatest benefit to mankind
The UK is leading the world in basic science and research and the NHS offers a unique environment to bring the research findings to the benefits of patients and their families. The BHF is committed to continue to support the adoption of innovation at scale and pace, to avoid the tragedy of an avoidable sudden cardiac death, for the sake of the patients of today and future generations.
For more information
W: www.bhf.org.uk
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