The signs and symptoms of Marfan syndrome vary greatly, even among members of the same family. Some people experience only mild effects, but others develop life-threatening complications. In most cases, the disease tends to worsen with age.

Marfan syndrome features may include:

• Tall and slender build
• Disproportionately long arms, legs and fingers
• A breastbone that protrudes outward or dips inward
• A high, arched palate and crowded teeth
• Heart murmurs
• Extreme nearsightedness
• An abnormally curved spine
• Flat feet

Marfan syndrome is caused by a defect in the gene that enables your body to produce a protein that helps give connective tissue its elasticity and strength.

Most people with Marfan syndrome inherit the abnormal gene from a parent who has the disorder. Each child of an affected parent has a 50-50 chance of inheriting the defective gene. In about 25 percent of the people who have Marfan syndrome, the abnormal gene doesn't come from either parent. In these cases, a new mutation develops spontaneously.

Marfan syndrome affects men and women equally and occurs among all races and ethnic groups. Because it's a genetic condition, the greatest risk factor for Marfan syndrome is having a parent with the disorder.

Because Marfan syndrome can affect almost any part of your body, it may cause a wide variety of complications.

Cardiovascular complications

The most dangerous complications of Marfan syndrome involve the heart and blood vessels. Faulty connective tissue can weaken the aorta — the large artery that arises from the heart and supplies blood to the body.

• Aortic aneurysm. The pressure of blood leaving your heart can cause the wall of your aorta to bulge out, like a weak spot in a tire. In people who have Marfan syndrome, this is most likely to happen at the aortic root — where the artery leaves your heart.
• Aortic dissection. The wall of the aorta is made up of layers. Dissection occurs when a small tear in the innermost layer of the aorta's wall allows blood to squeeze in between the inner and outer layers of the wall. This can cause severe pain in the chest or back. An aortic dissection weakens the vessel's structure and can result in a rupture, which may be fatal.
• Valve malformations. People who have Marfan syndrome can have weaker tissue than normal in their heart valves. This can produce stretching of the valve tissue and abnormal valve function. When heart valves don't work properly, your heart often has to work harder to compensate. This can eventually lead to heart failure.

Eye complications

Eye complications may include:

• Lens dislocation. The focusing lens within your eye can move out of place if its supporting structures weaken. The medical term for this problem is ectopia lentis, and it occurs in more than half the people who have Marfan syndrome.
• Retinal problems. Marfan syndrome also increases the risk of a detachment or tear in the retina, the light-sensitive tissue that lines the back wall of your eye.
• Early-onset glaucoma or cataracts. People who have Marfan syndrome tend to develop these eye problems at a younger age. Glaucoma causes the pressure within the eye to increase, which can damage the optic nerve. Cataracts are cloudy areas in the eye's normally clear lens.

Skeletal complications

Marfan syndrome increases the risk of abnormal curves in the spine, such as scoliosis. It can also interfere with the normal development of the ribs, which can cause the breastbone to either protrude or appear sunken into the chest. Foot pain and low back pain are common with Marfan syndrome.