Marfan syndrome can be difficult to diagnose because the signs and symptoms can vary from person to person.
In most cases, a diagnosis will be based on a thorough physical examination and a detailed assessment of a person's medical and family history.
There are a number of criteria that your GP or geneticist – a gene specialist – will measure your symptoms against.
Your doctor will carry out a physical examination, which should include:
- listening to your heart
- checking your skin for stretch marks
- looking for any physical features of the syndrome, such as a high palate, curvature of the spine, and long, thin arms and legs
As well as the varied signs and symptoms of Marfan syndrome, it can sometimes be difficult to distinguish the syndrome from other syndromes that affect the body's connective tissue, such as Ehlers-Danlos syndrome or Beals syndrome.
The Marfan Foundation (USA) has more infomation about disorders related to Marfan syndrome.
As well as carrying out a physical examination, your GP will have a detailed look at your:
- medical history – to find out whether you've had any symptoms or illnesses in the past that may be a sign of Marfan syndrome
- family history – if you have a close family member with Marfan syndrome, your chances of also having the syndrome are increased
Marfan syndrome can be particularly difficult to diagnose in children, and it's rare for it to be diagnosed in a young child.
This is because most of the signs and symptoms don't usually appear until later childhood and the teenage years.
If Marfan syndrome is suspected, your child will be carefully monitored so any developing symptoms can be detected and treated as soon as possible.
Your GP may compare the signs and symptoms against the Ghent criteria. This is a diagnostic tool that helps GPs and other healthcare professionals tell the difference between Marfan syndrome and other similar syndromes.
The Ghent criteria consists of major and minor criteria. The major criteria are features or symptoms common in people with Marfan syndrome that are rare in people who don't have it.
Minor criteria are features or symptoms present in people with Marfan syndrome, but are also present in people who don't have it.
To be diagnosed with Marfan syndrome using the Ghent criteria, you must have a number of different symptoms.
If you have a family history of Marfan syndrome, you'll need to have one of the major criteria and one of the minor criteria.
If you don't have a family history of Marfan syndrome, you'll need to have two major criteria and one of the minor criteria.
Some of the major and minor criteria used to help diagnose Marfan syndrome are listed below.
Major criteria can include:
- an enlarged aorta
- a tear in the aorta
- dislocation of the lens of the eye
- a family history of the syndrome
- at least four skeletal problems, such as flat feet or curved spine (scoliosis)
- enlargement of the lining that surrounds part of the spinal cord (dural ectasia)
Minor criteria can include:
Your GP may arrange for you to have some additional tests at a hospital or clinic. This will help detect any potentially serious symptoms, such as an enlarged aorta.
Some of the tests you may have include:
- an eye examination – this is carried out by a doctor who specialises in eye conditions (ophthalmologist) to check for dislocation of the lens
- an echocardiogram – where sound waves are used to produce an image of your heart, allowing doctors to check for heart problems and any problems with your aorta
- a chest X-ray – an imaging technique that uses high-energy radiation to highlight abnormalities in bones and certain organs of the body, such as the heart and lungs
- a magnetic resonance imaging (MRI) scan – uses a strong magnetic field and radio waves to produce a detailed image of the inside of your body; it can be used to examine your aorta and other blood vessels, and detect dural ectasia
Although the gene that causes Marfan syndrome has been identified, it can change (mutate) in more than 3,000 different ways. Genes are single units of genetic material.
A genetic test can be used to examine the gene responsible for Marfan syndrome. It's able to detect an error that causes the syndrome in 99% of those affected. However, the test is expensive and takes three months to complete.
In most cases, a diagnosis of Marfan syndrome will be made from the physical features and symptoms of the syndrome.
Read more about genetic testing and counselling.
Once a gene mutation for Marfan syndrome has been found, and you're going to become a parent, you may want to have your unborn baby tested to find out whether they also have the syndrome.
There's a one in two (50%) chance of the baby inheriting the syndrome.
To do this, two possible tests can be used – chorionic villus sampling (CVS) or amniocentesis.
Chorionic villus sampling
Prenatal testing for Marfan syndrome can be carried out approximately 10 to 12 weeks into the pregnancy using chorionic villus sampling (CVS).
CVS involves taking a small sample of cells from the organ that links the mother's blood supply with her unborn baby's (the placenta) through the entrance of the womb. The sample can then be tested for genetic conditions.
Amniocentesis can also be used to test for Marfan syndrome. The test is carried out about 16 to 18 weeks into the pregnancy and involves taking a small sample of amniotic fluid for examination. Amniotic fluid surrounds the unborn baby in the womb.
Although prenatal tests may show whether your child has the defective gene that causes Marfan syndrome, the tests won't give any indication as to how serious their symptoms will be. Generally, the baby will be affected to the same extent as other people in their family.
The severity of Marfan syndrome in the parent is an indication of how severe it will be in the child. Your child may only experience very mild symptoms, despite having the genetic mutation. This is because the expression of the gene can vary, even within the same family.
In some cases, the results of CVS or amniocentesis could be negative, suggesting that your child doesn't have the defective gene. However, your child may have a different genetic mutation that wasn't tested for, but could still cause Marfan syndrome.
Preimplantation genetic diagnosis
Preimplantation genetic diagnosis (PGD) is a technique where eggs and sperm are harvested from the parents so embryos can be created in a laboratory.
Only unaffected embryos are available for implantation in the womb. The process takes about 12 months.
PGD is only an option after a person with Marfan syndrome has been identified as having a Marfan gene mutation and wants to become a parent. The NHS will fund a couple to have one unaffected child by PGD.