Marfan syndrome, according to Dr Rosalyn S. De Witt, is an inherited disease that affects the connective tissue within the body. This results in a variety of skeletal deformities, as well as problems with the heart and the blood vessels.
Marfan syndrome is known to be a dominant genetic disorder, which means that a person needs to inherit only one defective gene in order, to actually have the syndrome. In addition to those cases of Marfan's which are clearly inherited, 20% of all Marfan's patients have no family history of the syndrome. It is believed that these patients have undergone a spontaneous genetic mutation leading to the syndrome. Interestingly, one risk factor for Marfan syndrome (in a family where Marfan's is not already an inherited disorder) is an elderly father. Marfan syndrome is said to have variable expression, meaning that either all, or only a few, of the classic signs of Marfan syndrome may occur in any given patient.
The biochemical problem, which results in Marfan syndrome has not been well defined. The groups of tissues affected by Marfan syndrome are called the connective tissues. These are tissues that are made of fibrous components, and they provide structural support for other body tissues. Included in the group called connective tissues are bone, cartilage, fat tissue, lymph tissue, and blood. The current belief is that the affected gene results in an abnormality in a protein called microfibrillin; and this protein is responsible for certain structural characteristics of connective tissue throughout the body.
Tourette syndrome.
According to David Aramer's article, Tourette syndrome (TS) is an inherited disease of the nervous system, first described more than a century ago by the pioneering French neurologist, Dr. George Gilles de la Tourette. Before age 18, patients with TS develop motor tics, that is, repeated, jerky, stereotyped, purposeless muscle movements in almost any part of the body.