Dr Anne Child is an Honorary Consultant in Genetics and Cardiology at St George’s, University of London, and is also involved in the service and research programme for Marfan Syndrome. During this interview, Dr Child speaks with Cardio Debate about this inherited disorder of the cardiovascular system.
What is the magnitude of the problem in the UK and worldwide regarding prevalence and cardiac events?
I run the Marfan Syndrome Service and Research Programme, and we’re mainly interested in diagnosis and management of this inherited condition. It’s directly transmitted from parent-to-child with a 50 per cent risk. It affects one in 3300 patients worldwide, and here in England we have 18,000 whom we know are affected, but there should be many more.
And it contributes to sudden cardiac death, seven per cent of sudden cardiac death is due to ruptured aneurysms.
Clinical clues to diagnosis
Well the diagnosis is often suggested by the involvement of the eyes, the heart, or the skeleton.
These patients, in 40 per cent of them, had dislocated lenses, so ophthalmologists should be aware. Often they are very tall and thin, with long, thin arms and legs, or fingers. Often a dip in the chest or curve in the back – so the skeletal features can also be a clue.
And of course from a cardiac point of view, chest pain or a family history of aneurysm or rupture is very important.
Where should GPs refer their patients with suspected Marfan?
The usual route of referral to make a diagnosis is through the Regional Genetics Unit. And these are available all over the UK. Indeed special Marfan clinics have been set up, manned by a cardiologist and a geneticist in 21 centres.
But the Regional Genetics Unit is the best place to start for a diagnosis.
There is a genetic test for the gene that causes Marfan syndrome, namely Fibrillin-1. And in 99 per cent of classical cases of Marfan syndrome we find an error that confirms the diagnosis, and can also be used to screen family members, and even to plan an unaffected pregnancy.
Available treatments and ongoing trials
Here at St George’s University of London, we have a very comprehensive management programme which ensures an almost normal lifespan. So if this is diagnosed early in life it certainly can be managed.
There are medications available – atenolol or beta-blocker is the basis of treatment, usually. This drops the blood pressure and slows the rate of the aortic expansion. That’s the main life-threatening event in Marfan syndrome – if the thin aortic wall ruptures and no-one knows it’s going to happen.
We can predict this with echocardiography once a year, we can treat with medication, and when the time comes for surgery – when the aortic route is over 4.5 cm – then we can offer open-heart corrective surgery with only a one per cent risk. And most of our patients do lead a normal lifespan.
We have a drug trial underway which is funded by the British Heart Foundation, called the AIMS trial. And our aim is to try and prove that losartan, irbesartan, this newer category of drugs is actually better than the old category of beta-blocker.
We’re fully recruited, we have 200 patients nationwide. And the results are due in 2018 and will be made available as soon as we have them.
But this promises either a supplementary treatment, or an even better life-saving treatment.