Marfan syndrome

Answer 1

Definition

Marfan syndrome is a disorder of connective tissue, the tissue that strengthens the body's structures.

Disorders of connective tissue affect the skeletal system, cardiovascular system, eyes, and skin.

Causes, incidence, and risk factors

Marfan syndrome is caused by defects in a gene called fibrillin-1. Fibrillin-1 plays an important role as the building block for elastic tissue in the body.

The gene defect also causes too much growth of the long bones of the body. This causes the tall height and long arms and legs seen in people with this syndrome. How this overgrowth happens is not well understood.

Other areas of the body that are affected include:

• Lung tissue
• The aorta, the main blood vessel that takes blood from the heart to the body may stretch or become weak (called aortic dilation or aortic aneurysm)
• The eyes, causing cataracts and other problems
• The skin
• Tissue covering the spinal cord

In most cases, Marfan syndrome is inherited, which means it is passed down through families. However, up to 30% of cases have no family history. Such cases are called "sporadic." In sporadic cases, the syndrome is believed to result from a spontaneous new gene defect.

Symptoms

People with Marfan syndrome are usually tall with long, thin arms and legs and spider-like fingers -- a condition called arachnodactyly. When they stretch out their arms, the length of their arms is much greater than their height.

Other symptoms include:

• A chest that sinks in or sticks out -- funnel chest (pectus excavatum) or pigeon breast (pectus carinatum)
• Coloboma of iris
• Flat feet
• Highly arched palate and crowded teeth
• Hypotonia
• Joints that are too flexible
• Learning disability
• Movement of the lens of the eye from its normal position (dislocation)
• Nearsightedness
• Small lower jaw (micrognathia)
• Spine that curves to one side (scoliosis)
• Thin, narrow face

Signs and tests

The doctor will perform a physical exam. There may be hypermobile joints and signs of:

• Aneurysm
• Collapsed lung
• Heart valve problems

An eye exam may show:

• Defects of the lens or cornea
• Retinal detachment
• Vision problems

The following tests may be performed:

• Echocardiogram
• Fibrillin-1 mutation testing (in some people)

An echocardiogram should be done every year to look at the base of the aorta.

Treatment

Vision problems should be treated when possible. Take care to prevent scoliosis, especially during adolescence.

Medicine to slow the heart rate may help prevent stress on the aorta. Avoid participating in competitive athletics and contact sports to avoid injuring the heart. Some people may need surgical replacement of the aortic root and valve.

People with Marfan syndrome should take antibiotics before dental procedures to prevent endocarditis. Pregnant women with Marfan syndrome must be monitored very closely because of the increased stress on the heart and aorta.

Support Groups

National Marfan Foundation -- www.marfan.org

Expectations (prognosis)

Heart-related complications may shorten the lifespan of people with this disease. However, many patients survive well into their 60s. Good care and surgery may extend the lifespan further.

Complications

Complications may include:

• Aortic regurgitation
• Aortic rupture
• Bacterial endocarditis
• Dissecting aortic aneurysm
• Enlargement of the base of the aorta
• Heart failure
• Mitral valve prolapse
• Scoliosis
• Vision problems

Calling your health care provider

Experts recommend genetic counseling for couples with a history of this syndrome who wish to have children.

Prevention

Spontaneous new gene mutations leading to Marfan (less than 1/3 of cases) cannot be prevented. If you have Marfan syndrome, see your doctor at least once every year.

References

Pyeritz RE. Inherited diseases of connective tissue. In: Goldman L, Ausiello D. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 281.

Robinson LK, Fitzpatrick E. Marfan syndrome. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 700.