An inherited disorder affecting about one person in 50,000 in which the CONNECTIVE TISSUE is abnormal. The result is defects of the heart valves, the arteries arising from the heart, the skeleton and the eyes. The victims are unusually tall and thin with a particular facial appearance (the US President Abraham Lincoln was said to have Marfan's) and deformities of the chest and spine. There are very long fingers and toes and their joints and ligaments tend to be weak. Orthopaedic intervention may help, as will drugs to control the heart problems. Medical follow-up is essential to detect and treat complications such as aortic ANEURYSM. As affected individuals have a 50 per cent chance of passing on the disease to their children, they should receive genetic counselling.