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Marfan syndrome is a genetic disorder arising from mutations in the fbn1 GENE that affect the structure of connective tissues throughout the body. The fbn1 gene encodes for fibrillin 1, a protein molecule essential for the formation of elastin. Elastin is the basis of the fibers that form the connective tissues. In Marfan syndrome the elastin is too soft, allowing connective tissues to stretch more than normal. The INHERITANCE PATTERN for Marfan syndrome is autosomal dominant, meaning one parent who has the mutated gene can pass the condition to his or her children. Marfan syndrome primarily affects the cardiovascular system, musculoskeletal system, and eyes.
Symptoms of Marfan syndrome and Diagnostic Path
Marfan syndrome produces hallmark physical characteristics that include
- tall, lanky frame with extraordinarily long arms
- elongated, narrow face
- crowded TEETH
- narrow, sunken chest
- long, thin fingers
Many people who have Marfan syndrome have severe MYOPIA (nearsightedness) and abnormalities of the CORNEA. Within the body, one of the most significant effects of Marfan syndrome is on the major BLOOD vessels, notably the AORTA, and the HEART valves. Because the connective tissue within the walls of the arteries is softer than it should be, the walls of the arteries are susceptible to separation (ANEURYSM). As well, the heart valves are often larger than normal and do not close properly, allowing blood to backflow within the heart. Mitral valve prolapse is the most common manifestation of this aspect of Marfan syndrome. To compensate, the heart intensifies the STRENGTH and frequency of its contractions, which over time enlarges the heart (CARDIOMYOPATHY).
There are no definitive diagnostic tests for Marfan syndrome, and symptoms are sometimes mild enough to escape detection until midlife or later when cardiovascular problems begin to emerge. An accumulation of symptoms points to the diagnosis, particularly if there is a family history of Marfan syndrome. The doctor may conduct GENETIC TESTING for the fbn1 gene MUTATION to confirm the diagnosis.
Marfan syndrome Treatment Options and Outlook
Treatment focuses on early detection of and therapy for potential complications, notably CARDIOVASCULAR DISEASE (CVD). Doctors advise against activities, especially competitive sports, that cause rapid and extreme changes in BLOOD PRESSURE and HEART RATE. Treatment may include medications to maintain low blood pressure and heart rate as preventive measures. Most people who have Marfan syndrome should have an ECHOCARDIOGRAM (ULTRASOUND examination of the heart) annually to screen for changes in the heart’s size and valve function and the stability of the aorta. Early surgery to intervene when echocardiogram suggests a dissecting aortal aneurysm can be lifesaving.
Risk Factors and Preventive Measures
Because cardiovascular complications of Marfan syndrome can be severe or life threatening, doctors recommend GENETIC COUNSELING for people who have the disease. Marfan disease is preventable only by preventing transmission of the mutated bfn1 gene. For the 30 percent or so of people in whom the mutation is spontaneous (occurs without apparent family history of the condition), there are no measures of prevention.
See also GENETIC DISORDERS.