The Marfan syndrome is a medical condition and is classified as a heritable disorder of connective tissue.
Connective tissue (including the extra-cellular matrix) is the glue and the scaffolding of the body, but is important in many more functions as well, such as development before birth, growth after birth, cushioning of joints, and enabling passage of light through the eye. All organs contain connective tissue, and the manifestations of the Marfan syndrome appear in many parts of the body, especially in the bones and ligaments (the skeletal system), the eyes (the ocular system), the heart and blood vessels (the cardiovascular system), the lungs (the pulmonary system), and the fibrous membrane covering the brain and spinal cord (the nervous system).
The condition is named after a French paediatrician, Antoine Marfan, who in 1896 described a 5-year-old girl whose arms, legs, fingers and toes were disproportionately long and thin, whose muscle development was poor, and whose spine curved abnormally. Subsequent physicians described other patients with similar skeletal changes as well as eye problems. By the early part of the Twentieth Century, as a form of medical shorthand, Marfan's name became commonly used to refer to individuals who seemed to be affected by this condition. The term "syndrome" refers to the fact that a group of physical signs or changes occur together often enough for a pattern to be recognized.
There are over 200 different heritable disorders of connective tissue, including a few which closely resemble the Marfan syndrome. They are termed "heritable" because all have their basis in a change (mutation) in one gene or another and, because relatives have genes in common, these conditions may affect more than one person in a family. Not all are inherited in the same pattern as the Marfan syndrome.