- Marfan syndrome type 1
- Contractural arachnodactyly
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Most people with Marfan syndrome have abnormalities of the heart and the aorta. Leaks in valves that control blood flow through the heart can cause shortness of breath, fatigue, and an irregular heartbeat felt as skipped or extra beats (palpitations). If leakage occurs, it usually affects the mitral valve, which is a valve between two chambers of the heart, or the aortic valve that regulates blood flow from the heart into the aorta. The first few inches of the aorta can weaken and stretch, which may lead to a bulge in the blood vessel wall (an aneurysm). The increased size of the aorta may cause the aortic valve to leak, which can lead to a sudden tearing of the layers in the aorta wall (aortic dissection). Aortic aneurysm and dissection can be life threatening. 
The Human Phenotype Ontology provides the following list of signs and symptoms for Marfan syndrome. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms.
The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature.
The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined.
Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.
- What Are the Signs and Symptoms of Marfan Syndrome?. National Heart Lung and Blood Institute. 2010; http://www.nhlbi.nih.gov/health/health-topics/topics/mar/signs.html. Accessed 10/15/2013.