Your doctor will diagnose Marfan syndrome based on your medical and family histories, a physical exam, and test results. He or she also will consult a set of guidelines called Ghent criteria, which are used to diagnose Marfan syndrome.
                
Marfan syndrome can be hard to diagnose. This is because its signs, or traits, are the same as or similar to the signs of other connective tissue disorders.
                
If you're diagnosed with Marfan syndrome, all of your first-degree relatives (for example, parents, siblings, and children) also should be checked for the disorder. This is because, even in families, the outward traits of Marfan syndrome may vary quite a bit.
                
Specialists Involved
                
Your family doctor or another type of doctor, such as an orthopedist (bone specialist), may notice certain traits that suggest Marfan syndrome.
                
If so, your doctor will likely refer you to a geneticist or cardiologist. A geneticist is hereditary disease expert. A cardiologist is a heart specialist. These two types of specialists often have the most experience working with people who have Marfan syndrome.
                
A geneticist will ask for medical information about you and your family. He or she will examine you and perhaps other members of your family. The geneticist also will coordinate your visits with other doctors, including a cardiologist, an ophthalmologist (eye specialist), and an orthopedist.
                
After reviewing the medical findings, the geneticist will determine whether you have Marfan syndrome.
                
Medical and Family Histories
                
Your doctor will ask about your medical history and your family's medical history. For example, your doctor may ask whether:
                
You've had heart disease, eye problems, or problems with your spine. These complications are common in people who have Marfan syndrome.
                
You have shortness of breath, palpitations, or chest pain. These are common symptoms of heart or lung problems linked to Marfan syndrome.
                
Any of your family members have Marfan syndrome, have died from heart problems, or have died suddenly.
                
Physical Exam
                
During the physical exam, your doctor will look for Marfan syndrome traits. For example, he or she may check the curve of your spine and the shape of your feet. Your doctor also will listen to your heart and lungs with a stethoscope.
                
Diagnostic Tests
                
Your doctor may recommend one or more of the following tests to help diagnose Marfan syndrome.
                
Echocardiography
                
Echocardiography (EK-o-kar-de-OG-ra-fee), or echo, is a painless test that uses sound waves to create pictures of your heart and blood vessels.
                
This test shows the size and shape of your heart and the diameter of your aorta or other blood vessels. (The aorta is the main artery that carries oxygen-rich blood to your body.) Echo also shows how well your heart's chambers and valves are working.
                
For people who have Marfan syndrome, echo mainly is used to check the heart's valves and aorta.
                
Magnetic Resonance Imaging and Computed Tomography Scans
                
Magnetic resonance imaging (MRI) is a test that uses radio waves and magnets to create detailed pictures of your organs and tissues. Computed tomography (CT) uses an x-ray machine to take clear, detailed pictures of your organs.
                
MRI and CT scans are used to check your heart valves and aorta. These scans also are used to check for dural ectasia, a nervous system complication of Marfan syndrome.
                
Slit-Lamp Exam
                
For this test, an ophthalmologist (eye specialist) will use a microscope with a light to check your eyes. A slit-lamp exam can find out whether you have a dislocated lens, cataracts, or a detached retina.
                
Genetic Testing
                
In general, genetic testing involves blood tests to detect changes in genes. However, because many different genetic changes can cause Marfan syndrome, no single blood test can diagnose the condition.
                
Ghent Criteria
                
Because no single test can diagnose Marfan syndrome, doctors use a set of guidelines called Ghent criteria to help diagnose the condition. The Ghent criteria are divided into major criteria and minor criteria. Sometimes genetic testing is part of this evaluation.
                
Major criteria include traits that are common in people who have Marfan syndrome. Minor criteria include traits that are common in many people. Doctors use a scoring system based on the number and type of Ghent criteria present to diagnose Marfan syndrome.
                
Talk with your doctor about which traits you have and your likelihood of having Marfan syndrome.