An autosomal genetic disorder of the connective tissue in the human body, which affects several organ systems. The most seriously affected is the cardiovascular system; the leaflets of the mitral valve in the heart can become too loose, and pump blood less efficiently, as well as cause irregular heart rhythm. In the skeletal system, both scoliosis and unusual bone growth are common symptoms, resulting in a very tall, long-boned body shape. Myopia is also a symptom. It is believed today that Abraham Lincoln suffered from Marfan's.
As there is no specific test for the condition, and not all victims express all traits, Marfan's is very difficult to diagnose. The only way to do it currently is to get a full physical, then a checkout by a cardiologist, an opthomologist, and an orthopedist. Oh, you also need to bring a complete family history as well. Marfan's was discovered to be coded on chromosome 15 in 1991, so a genetic test might be more convenient in the future.
Marfan's can be treated, but not cured. Treatment basically means that you need to pay a bunch of money regularly to medical specialists to check your body out to make sure that your heart, skeleton, eyes, etc. are still OK. Sufferers of Marfan's should avoid strenuous activity.
Thanks to www.marfan.org for all but the Abe Lincoln bit.