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People with Marfan syndrome must be supported in starting families free of the disease

8 April 2013
By Dr Anne Child
Reader, cardiovascular genetics and honorary consultant in cardiology and genetics at St George's, University of London
Appeared in BioNews 699

So, the Human Fertilisation and Embryology Authority (HFEA) will review the list of approved inherited conditions for which preimplantation genetic diagnosis (PGD) is currently licensed.

As related by Professor Alan Handyside and colleagues at The Bridge Centre in an earlier BioNews, seven disorders, of which Marfan syndrome is one, have been selected for review.

The logic runs that as treatment and quality of life improve for people with these conditions, so afflicted families should have less entitlement to publicly funded PGD, which aims to prevent affected children being born.

I do not write to query that logic. I write to say that the HFEA must maintain its support for PGD in the case of Marfan syndrome.

Marfan syndrome is not curable. It begins at conception and by the time the infant is born there are already severe manifestations which will last a lifetime. These will not only affect the lifespan, but the quality of life.

Yes, lifespan is slowly improving due to improved medication (beta-blockers in particular) and surgery. However, my first contact with many of the families I see will be subsequent to a sudden unexpected death. There is insufficient awareness of Marfan syndrome so not all - or even the majority - of cases are diagnosed or treated.

Marfan syndrome has been calculated to affect one in 3,330 in Europe. By this estimate there should be 18,000 known Marfan syndrome cases in the UK. At a stretch, we know of approximately 9,000. Where are the rest? These are the ones who go undiagnosed and die suddenly.

These people may have also had families by the time they die suddenly so that the genetic defect is perpetuated in the gene pool. Moreover, 25 percent of cases are the result of de novo mutations - in other words the mutation occurs spontaneously at conception with no family history of the disease. These are usually more severe than the familial cases. Such people now benefit from more effective therapy, including surgery, and are therefore more likely to live into fertility. Their children have a 50 percent likelihood of inheriting this most severe form of the disease.

These patients should be allowed to start families free of the disease by using PGD. Without access to PGD, many will choose to remain childless.

Quality of life remains severely affected by the multi-system nature of Marfan syndrome. Patients do not just have dislocated lenses and aortic aneurysms to contend with. Their eyes may be affected by severe short-sightedness, by retinal detachment, and glaucoma.

The skeleton suffers from patients' excessive height for which we have no effective therapy. There are chest bone abnormalities, loose painful joints, scoliosis (often requiring surgery) and early, and very painful, osteoarthritis so that old age really starts around age 50.

With regard to the heart, as well as running the risk of fatal aortic dissection, patients suffer from prolapse of the heart valves, left ventricular failure, and endocarditis. Forty percent of patients have arrhythmias. So as well as dying at an early age, patients have very difficult lives. I hardly need mention the burden on the NHS.

Our research has also uncovered irritable bowel syndrome in 20 percent of cases, dental problems such as impacted teeth, and psychological problems such as depression, isolation and poor self-image.

Researchers and clinicians are working as quickly as we can (one major trial will publish its results in 2018) to find improved therapies in the form of losartan or irbesartan. There are 10 trials running internationally. Patients are enthusiastic about joining in, because they know how awful this condition is.

In short, Marfan syndrome is a terrible disease. Families must have access to PGD to limit the genetic impact on their families in the future.

SOURCES & REFERENCES
RELATED ARTICLES FROM THE BIONEWS ARCHIVE
18 February 2013 - by Professor Alan Handyside, Dr Karen Sage, Michael Summers and Dr Alan Thornhill 
The Human Fertilisation and Embryology Authority recently announced plans to review the list of approved inherited conditions for which preimplantation genetic diagnosis is currently licensed to ensure that it is only available for conditions which meet the statutory requirements in the UK...
1 August 2011 - by Rose Palmer 
A man who fathered at least 24 children by sperm donation in the US failed to inform fertility clinics that he had a rare genetic defect which is often fatal, ABC news has reported...
23 July 2010 - by Professor Alan Handyside 
At the beginning of this month, following the European Society for Human Reproduction and Embryology (ESHRE) annual meeting in Rome, a workshop was held to celebrate 20 years of preimplantation genetic diagnosis (PGD)...
5 July 2010 - by Dr Malcolm Smith 
This guide is invaluable for anyone who has an interest in preimplantation genetic diagnosis (PGD), particularly those who do not have a scientific background and are interested in the regulatory and ethical issues associated with this technology...
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